Abstract: Now Loran-C is one of important navigation equipments in ship, and Loran-C/INS integrated system plays an important role in naval ship in special period. In order to increase the integrated system’s precision, the wavelet’s reducing noise technique is introduced into Loran-C/INS integrated system to increase the signal-noise ratio of Loran-C, and then into Kalman filter, the dynamic and static experiment results based on practically measured data show that this method can obviously increases every navigation parameter’s precision, and can remove the position fault of Loran-C in a short time.