Abstract: A compatible identification algorithm （GPIA-MRIA） is presented, in which the Lainiotis' general partitioning identification algorithm （GPIA） is combined with the model reference identification algorithm （MRIA） based on the stability theory of Lyapunov. By means of this algorithm, the residuals of the system can approach to zero asymptotically and variance of the residuals can be minimized. In the GPIA-MRIA algorithm GPIA gives a linear optimal estimation of state and parameters according to a finite measurement set and MRIA offers an asymptotical approach of the models. This means that GPIA contributes the state estimator of MRIA on the one hand, and on the other hand MRIA predicts the parameters and adjusts the model of GPIA to an optimal estimation of the parameters.This method has been applied to identification of the aerodynamic coefficients (Cx0, Cxi, CY0, CYα, mz0,mzα,mzωz and the control derivatives （CYδ, mzδ） of an aircraft by means of digital simulation. It is shown that this method is evidently superior to the single GPIA in accuracy of identification and speed of convergence and requires almost no increase in the capacity of computation,