本文研究了高阶线性系统的一类最优简化模型.这类简化模型在脉冲输入时,其输出同原系统输出之间的误差按平方加权积分意义达到最小值,并且在幂函数和多项式输入时,其输出同原系统输出之间无稳态误差.本文推导了这类最优简化模型的必要条件,给出了单输入-多输出系统最优简化模型的数值例子和计算结果,并且同其他作者的最优简化模型作了比较.最后,本文还对多输入-多输出系统的最优简化模型给出了算法. In this paper, a class of optimal simplified models for higher-order linear systems is studied. The error between the output of the simplified model and the output of the original system reaches the minimum according to the square-weighted integral meaning at the time of pulse input. In the power function and the polynomial input , The steady-state error between the output of the system and the output of the original system is obtained.This paper deduces the necessary conditions of the optimal simplified model, gives the numerical examples and the calculation results of the optimal simplified model of single-input multiple-output system, Finally, this paper also gives the algorithm for the optimal simplified model of multiple-input-multiple-output system.