CAPM model is an equilibrium theory on how to price and measure risks and benefits. Its fundamental function is to confirm the relationship between expected return and risk, and reveal whether there is abnormal return in the market. The expected return of assets is related to the risk measurement of assets-β value. CAPM was put forward by william sharpe. The winner of the Nobel Prize in Economics, in his book Portfolio Theory and Capital Market 1970, is called the financial theory of the first mathematical revolution on Wall Street.