采用自寻优求解法建立小偏差状态变量模型(SVM),即先任意给定A,B,C,D矩阵,然后根据发动机非线性模型与状态变量模型的小偏差动态响应对比直接寻优A,B,C,D矩阵.求解目的为使状态变量模型与非线性模型的小偏差动态响应吻合,因而应用该方法可以保证所建模型具有较高的精度.此外该方法不受模型阶次的限制.应用该方法建立了某型涡轴发动机的小偏差状态变量模型,通过与非线性模型仿真结果比较,验证了该方法的有效性和准确性,所建立的状态变量模型可用于航空发动机控制系统设计与故障诊断. A small deviation state variable model (SVM) is established by using self-optimization method. That is to say, the A, B, C and D matrices are given arbitrarily. Then according to the small deviation dynamic response of the nonlinear model and the state variable model, , B, C and D. The purpose of the solution is to make the state variables model consistent with the small deviation dynamic response of the nonlinear model, so the method can ensure the high accuracy of the model.Furthermore, The small bias state variable model of a certain type of turboshaft engine is established by this method. The effectiveness and accuracy of this method are verified by comparison with the nonlinear model. The state variable model can be used in the control of aeroengine System Design and Troubleshooting.