This paper analyzes the policy effects of interest rate liberalization under strict inflation targeting and flexible inflation targeting, which is based on the new theory of Keynes model and the introduction of price stickiness in the framework of dynamic stochastic general equilibrium. By building, calibrating, estimating and simulating a new Keynesian DSGE model, we analyze and compare the effect of strict inflation targeting and flexible inflation targeting in the process of the interest rate liberalization. Research results show that, first of all, the strict inflation targeting regulation makes the output volatility smaller and the inflation volatility greater in face of technology shocks. Secondly, the flexible inflation target system is more conducive to controlling output and inflation in the short period when facing monetary policy shocks. Finally, the control of the strict inflation target is less from the point of view of the loss function. In other words, the central bank's loss function under the control of the strict inflation target system is small, but the flexible inflation targeting system is more conducive to controlling output and inflation in the short period.