Abstract: For studying the electronic jamming influence on the C/A code acquisition performance of GPS receivers, the mean acquisition time and variance of the acquisition of C/A code were analyzed. A simulation based on three jamming patterns, namely the CW, wide-band and part-band jamming patterns, has been carried out. The results have shown that both the mean acquisition time and variance of the acquisition will increase rapidly if the jamming power against GPS receivers is beyond a certain value. With the same signal-to-jamming ratio of intermediate frequency output, effect of CW jamming proved to be more predominant over that of wide-band jamming.