Guided by the strategic goal of building an innovative country, in order to cultivate the rapid development of small and medium-sized enterprises as the main body of technological innovation and give full play to the leverage amplification effect of financial funds, China began to set up venture capital guidance funds. After several years of operation, the venture capital guidance fund has achieved good results. However, due to the short operation time of venture capital guidance fund, some problems have become more and more prominent. For example, the ability of venture capital to guide the operation of the fund is insufficient; Conflict of goals among participants; The investment direction is chaotic; Complex principal-agent problems such as interest distribution and imperfect incentive and supervision mechanism. How to set up and manage venture capital guidance fund and improve the efficiency of government's use of guidance fund is an important topic before our government. Under this background, it is imperative to analyze the complex principal-agent relationship and nature in the management of government venture capital guidance fund and investigate the behavior characteristics of each participant in the operation of venture capital guidance fund. With the help of complexity and complex system theory, principal-agent theory and * * * same agent theory, this paper innovatively studies the principal-agent mechanism of venture capital guidance fund from the perspective of complex system by using theoretical research, model construction and empirical analysis, and puts forward the concept of principal-agent system of venture capital guidance fund. Based on the systematic perspective, this paper constructs the principal-agent model of internal management of venture capital guiding fund, obtains the principal-agent mechanism of internal management, and puts forward some suggestions on improving the current management model of guiding fund in China. At the same time, the principal-agent model of multi-task venture capital institutions, the core node of the system, is constructed, and the principal-agent mechanism of multi-task venture capital institutions is obtained. In addition, taking Zhejiang venture capital guidance fund as an example, it provides theoretical support for the actual operation of venture capital guidance fund. Through research, this paper has obtained the following research results and conclusions. (1) The operation of venture capital guidance fund is characterized by a complex system. The principal-agent system of venture capital guidance fund is composed of the overall presentation of multiple participants, multi-level structure, goals and time, openness to contact and exchange with the external environment, dynamic adaptability to various changes and self-organization in response to changes. The node elements of this system are government, guiding fund management institutions, social investors, venture capital institutions and venture enterprises, all of which are indispensable to the system; The relationship between node elements is a complex principal-agent relationship; Each node element has a strong sense of responsibility, and their behavior choice should be based on the principle of realizing the overall goal of the system-promoting the development of high-tech industries and small and medium-sized entrepreneurial enterprises; It can cope with external changes and has dynamic adaptability and self-organization. (2) Under the background of the principal-agent system of venture capital guidance fund, a reasonable principal-agent mechanism should be designed for the internal management of venture capital guidance fund in line with the principle of realizing the overall goal of the system. This paper constructs an incentive mechanism model to guide fund management institutions under symmetric and asymmetric conditions. Through the analysis model, it is concluded that under symmetrical conditions, as long as the government pays a reasonable salary to the guiding fund management institution, so that the marginal income of the guiding fund management institution's efforts is equal to its marginal cost, it will prompt the guiding fund management institution to adopt the optimal level of efforts; Under the condition of asymmetry, the guiding fund management institution should form a salary incentive mechanism combining fixed reward and floating reward. The incentive intensity in the optimal salary incentive contract is influenced by the professional ability of the guiding fund management institution, the degree of absolute risk avoidance, the coefficient of effort cost, the income variance of venture capital institutions, policy investment restrictions and other factors. Specifically, in the case of less policy restrictions, the guiding fund management institutions with high professional level, adventurous spirit, stable environment and low effort cost can increase the incentive intensity, so that they can work actively and get the maximum benefits. (3) From the point of view of complex system, some suggestions are put forward to improve the internal management mode of venture capital guidance fund in China. It is pointed out that both the direct management mode and the entrusted social organization management mode should be based on the principle of realizing the overall goal of the system-promoting the development of high-tech industries and small and medium-sized entrepreneurial enterprises, and design the incentive mechanism to guide the fund management institutions according to local conditions, so as to strike a balance between incentive and insurance. Among them, the venture capital guiding fund, which implements the management mode of public institutions, should form a salary incentive mechanism combining fixed rewards and floating rewards to prevent agents from not working hard and seeking rent; For the venture capital guidance fund that implements the management mode of state-owned companies, we should pay attention to mastering and adjusting the establishment mode and income distribution mode, and carry out necessary constraints and supervision on state-owned companies to prevent neglect of "policy strategy"; Entrepreneurial investment guidance funds entrusted to social institutions should determine different incentive intensity according to specific conditions, and the interval of incentive intensity is (0, 1) to prevent serious principal-agent problems. (4) Venture capital institutions have the dual alternative tasks of supporting enterprises with investment policies and investing in high-yield enterprises. By constructing the principal-agent model of investors and multi-task venture capital institutions, it can be concluded that the substitution of the two tasks weakens the incentive effect of multi-task reward mechanism. The same degree of incentive will make venture capital institutions reduce their energy to the task of supporting enterprises with investment policies, that is, they often ignore the "policy objectives" of venture capital guidance funds. By weakening the task substitution of venture capital institutions, or changing the task of substitution relationship of venture capital institutions into the task of complementary relationship, the goal of system integrity will be greatly promoted. (5) From the point of view that it is beneficial to the orderly operation of the principal-agent system of venture capital guidance fund, and based on the principle of weakening the task substitution of venture capital institutions, or transforming the alternative tasks of venture capital institutions into complementary tasks, this paper puts forward the multi-task principal-agent mechanism of venture capital institutions. Specifically, it includes: the identification and cultivation mechanism of high-quality investment projects, the selection mechanism of venture capital institutions with industry characteristics, the shareholding restraint mechanism of phased funds, the performance evaluation mechanism of multi-task venture capital institutions combining subjective and objective, the reasonable supervision mechanism of multi-task venture capital institutions and the reputation mechanism of multi-task venture capital institutions.