Abstract: Inertial navigation system(INS) is the primary navigation methods for submarine.In order to attain passive navigation,in this paper gravity anomaly and geomagnetic intensity anomaly grid data are used to correct the drifting error of the INS.The gravity anomaly grid data is derived from satellite altimetry inversion.The geomagnetic anomaly grid data is extracted from Earth Magnetic Anomaly(EMAG2).The two grid data are both with the resolution of 2 arc-minute.In western Pacific Ocean two special regions with distinct gravity and geomagnetic features are selected to carry out the simulation test on gravity and geomagnetic aided navigation with SITAN algorithm separately.The simulation result indicates that there is a close relationship between the gravity and geomagnetic feature along the trajectory and the result of aided navigation.The navigation precision attain 2 n mile under various circumstances.