Abstract: In MEMS_SINS/GPS integrated navigation systems, there exist uncertain/unknown disturbances, and the output of GPS often contains fault signals. In order to deal with these problems, an H∞ faulttolerant filter is proposed, which is robust against uncertain disturbances and can take faulttolerant computation after a fault is detected. With this function, the filtering accuracy is kept in the required range during the whole process. Based on the H∞ filter, weighting factors are added into the state estimation equation. In addition, the measurement component is weighted individually so that this algorithm is applicable to the situation with very different measurement magnitude. The simulation results show that it can significantly reduce the impact of the fault signals and the system can work in the normal range.