The method for aeroengines' state variable model(SVM)identification was implemented by using the linear relation of the variable of the differential equations

and separating the steady process and transient process to eliminate the steady errors coupled by transient process. Without solving the differential equations or using any iterative methods

the coefficient of the SVM could be acquired simply using matrix operation

so it has a higher computational efficiency than former least square method. And this method might also be combined with other identification method to realize better effect. Finally

to illustrate the validity and accuracy of the proposed method

a small perturbation SVM of some turbo-shaft engine model had been established through it

and the simulation results from the engine's state space model and nonlinear model were compared

and we can draw a conclusion that the SVM got by this method meets the dynamic and static objectives well

though the plant has a severe nonlinearity.