For the existing double power reaching law,the chattering problem of exponential approach law affects the use of sliding mode control in practice,and results in the defects of too slow global convergence speed and long time.To overcome the problems,an improved double power exponential approach law was proposed.In the proposed double power exponential approach law,the design of variable exponential term was adopted.That was,the sliding mode control process was divided into two parts when reaching the sliding surface.When the absolute value of the state was less than 1,the system entered smoothly along the sliding surface,and the buffeting effect was negligible;when the absolute value of the state was greater than or equal to 1,the dynamic response of the system was significantly improved,the convergence time was shortened,and the total time was less than the sum of the time when the initial state moved to the critical value and the time when the system moved to the sliding surface equilibrium point.It is theoretically verified that the improved double power exponential approach law can quickly converge to the equilibrium point and eliminate the buffeting effect,and the effectiveness of the approach law is verified through experimental simulation comparison.Comparing multiple reaching laws，the improved double power exponential reaching law has the best performance and the fastest convergence speed.The experimental results show that the reaching law can still converge to the equilibrium point rapidly under external interference.