We propose an analytical hierarchy process（AHP） based inertial navigation system（INS） / gravity integrated system accuracy performance evaluation approach.INS / gravity integrated system is firstly analyzed to classify its key error factors.Then we use these factors to establish a multilayer systematic error description model for the application of AHP.To solve the problem of the weight model description of traditional AHP and objectively determine the evaluation weight of each factor

a combined threshold and traverse to determine performance value of system is designed.Finally

a practical application exampleshows the effectiveness of the accuracy performance evaluation approach.This method can evaluate the performance of INS / gravity integration system

and then service for the modification of this system and has certain practical significance.