Abstract: Based on the introduction and analysis of the approach of H_∞ loop shaping,aiming at the problems that the weight functions are chosen by trial and error,and the synthetical performance index of the controller is hard to meet the frequency and time domain performance requirements,an improved weight function selection method is proposed based on engineering design and chaos optimization.Compared with normal weight selection method,the new method can reduce the iteration times of weight function selection,and ensure the synthetical performance of the resulting H_∞ loop shaping controller.Simulation results demonstrate that it is easy and effective to use the improved selection method to design controller and the controller can meet the design demands better.