To solve the problems of low real-time performance and easy environmental impact in soft fault detection of redundant strapdown inertial navigation system (SINS), an APV/ FASPRT algorithm is proposed. Firstly, the parity space is constructed according to the hardware redundancy configuration, SPRT algorithm is implemented for the parity residual, and the fading factor and periodic reset are introduced to improve the tracking speed of the current residual information. Secondly, APV algorithm is used to detect the fault end time to reset the fading SPRT and provide sensitive axis information. In order to enhance the stability of fault detection, a threshold determination method based on the admissibility fault is proposed for the four and six gyro redundancy configurations commonly used in engineering. The simulation results show that compared with GLT, SPRT and APV methods, the average detection delay of the proposed algorithm is reduced by 50. 59%, 70. 21% and 2. 32%, and the average false alarm rate is reduced by 69. 31%, 99. 33% and 64. 77%, respectively. The real time of soft fault detection is enhanced and the false alarm rate is reduced in normal running time.