This paper analyses the main factors affecting aircraft performance degradation in QAR data, uses the optimal weighted data fusion algorithm and the extended Calman filter algorithm for the estimationof state parameter which are related to aircraft performance parameters. When there is less external environment effect, the convenience of the optimal weighted fusion algorithm is verified, and when the effect is overlarge, the precision of this algorithm is limited. Thus we use the extended Calman filter algorithm, take Gauss noise into account, and improve the accuracy of state estimate for the airline to improve the operation of the aircraft provides a reference.