Three principles of commercial banks: safety, liquidity and profitability are the operating principles of commercial banks, and safety is the first operating principle of commercial banks. Liquidity is not only a necessary means to achieve security, but also a balance lever between profitability and security. Maintaining moderate liquidity is a strategic means for commercial banks to operate; Safety is the basis of profit, which in turn ensures safety and liquidity. Therefore, prudent commercial banks always pursue profit maximization on the premise of maintaining security and liquidity.

Security means that commercial banks should try their best to avoid the influence of various uncertain factors and ensure the operation and development of commercial banks. The reason why commercial banks must adhere to the principle of safety is because of the particularity of commercial banks' operation. Reasons: ① Commercial banks have little self-owned capital and can't afford big losses. ② The particularity of commercial banks' operating conditions, especially their security. (3) Commercial banks will face various risks in the course of operation.

Liquidity refers to the ability of commercial banks to meet customers' demand for cash withdrawal and necessary loans at any time, including the liquidity of assets and liabilities. Liquidity of assets refers to the ability to realize assets quickly without loss, which refers to both quick assets and the ability to convert other assets into quick assets without loss when quick assets are insufficient.

Profitability, all operating enterprises have a common goal-the pursuit of profitability. Commercial banks concentrate idle funds of enterprises, institutions and individuals by absorbing deposits and issuing bonds, and then use the concentrated funds to make up for the temporary shortage of funds of some enterprises, institutions and individuals.

The relationship between the three is often the contradiction between the three characteristics of commercial banks. From the perspective of profitability, the assets of commercial banks can be divided into profit assets and non-profit assets. The higher the proportion of funds used for capital and profitable assets, the higher the interest charged by commercial banks and the larger the profit scale. From the perspective of liquidity, non-profit assets such as cash assets can be used to meet the demand for deposits at any time, and the liquidity is sufficient. Therefore, the higher the inventory of cash assets, the stronger the coping ability of the commercial banking system and the stronger the liquidity of commercial banks. From the perspective of security, generally speaking, assets with higher returns are always risky. In order to reduce risks and ensure the safety of funds, commercial banks have to put in rate of return on capital's low assets. In fact, there is a potential unified and coordinated relationship among the three principles of commercial bank operation.