Considering the distributed intermittent interference threat faced by global navigation satellite system receiver, the anti-jamming performance of STAP (space-time adaptive processing) based on sample matrix inversion method was comprehensively and accurately analyzed. Based on the performance analysis model, according to the mismatch of sampling covariance matrix caused by intermittent interferences, the performance of STAP under different conditions was comprehensively analyzed through classification evaluation, combing induction and theoretical derivation. The analysis results show that when the sampling length is less than the scintillation period and the pre-sample method is used, the missed sampling of space-time adaptive processor will occur and the interference suppression performance will decrease sharply, and the frequency of missed sampling is the sum of the scintillation frequencies of each interference. Numerical and simulation analyses verify the results of analysis, and based on this, the optimal design of STAP in the face of distributed intermittent interference is discussed.