Abstract: A correlation analysis algorithm has been researched to find out correlation among model updates,engine inputs and its component performance.This work is required for development of an on-board real-time engine model which is based on component tracking filters,and also is significant for modern control algorithm and analytical redundancy technique to be applied to engine control.The results of numerical simulation show that the correlation analysis not only can reduce calculation work,but also enable the model developed track and match engine very well,even under the condition that the number of sensors is limited.