In the process of investment, investors whether institutional investors or investors adjust a portfolio when they are in the event of loss or expected loss occurs. In other words, investors adjust the portfolio is designed to ensure the combination can obtain the income. Based on this idea, a dynamic portfolio model is established by using the PID controller. The model puts the error between the portfolio expected return rate and a given yield as a control variable, and dynamically adjusts the securities portfolio weights using the PID controller, to achieve the target which the expected portfolio return rate reaches the given yield. A simulation result shows that the portfolio expected return rate according to the dynamic portfolio model can achieve the given return which is determined at the beginning of investment.