Securities investment fund is an indirect investment method that concentrates investors' funds by issuing fund shares, which are managed by fund trustees and managed and used by fund managers, and invests in financial instruments such as stocks and bonds, and distributes investment income according to the investment proportion of fund investors. It is a way of trust investment. Like the general financial trust relationship, there are mainly three parties: the principal, the trustee and the beneficiary, among which there is a trust deed between the trustee and the principal.