The extended Kalman filtering(EKF) is the primary mechanism used in nonlinear systems.The unscented Kalman filtering(UKF) is a new nonlinear filtering method,which propagates the first two moments as EKF does,while does not need to calculate the Jacobian matrix.The EKF and UKF are both applied to the INS/GPS integration system in this paper.The simulation results show that the UKF is more appropriate for the INS/GPS system than the EKF.