Characteristic of strapdown inertial navigation system(SINS) and its application to guiding,navigation and control(GNC) of miniature type unmanded air vehicle(UAV) are discussed in this paper.As a complementarity,the algorithm of SINS and the SINS/GPS(Global Positoning System)integrated navigation system are analysed.The result indicates that the algorithm and the integrated system based on SINS can meet the GNC-specification of UAV and has a good prospect in this area.