1, safety principle, social security fund is a special fund, which is the "life-saving money" of the insured. In order to ensure that social insurance institutions have sufficient repayment ability, the investment and operation of social security funds must abide by the principle of safety, so that funds can flow back safely. Most countries stipulate by legislation that social security funds must invest in safe assets, so national debt, as a "gilt bond", often becomes the first. However, the rate of return on safe assets is low, so it is difficult to maintain and increase the value of funds under normal circumstances.

2. Liquidity principle: the liquidity of fund investment refers to the ability of an asset invested by a fund to be converted into cash at any time without losing its original value. In order to meet the needs of medical treatment, industrial injury and other insurance at any time, the funds put into operation can maintain a certain liquidity. Among all kinds of assets, bonds and bank deposits have strong liquidity, but their returns are low, especially when time deposits are withdrawn in advance, interest income is often lost. Real estate investment has high returns and poor liquidity. For different social insurance projects, due to different uses of funds, the liquidity requirements are different: unemployment, sickness and disability insurance funds have higher liquidity requirements and often invest in short-term or medium-term projects; Pension funds have a long cycle and can invest in long-term projects.

3. The principle of profitability. In the final analysis, the preservation and appreciation of social security funds depends on the income from investment. Without income, it is impossible to preserve value, let alone increase value. Therefore, the investment of social security fund must be profitable, so as to further improve the level of social security fund and promote the development of social security, social progress and economic prosperity.