CDMA communication system has a certain anti-interference performance, but when the interference is stronger, the performance and stability of system will descend obviously. In this paper, narrow-band interference suppression based on FFT transform is adopted to improving anti-interference performance of CDMA communication systems significantly. Probability and statistics search for interference signal is used in frequency domain, which increases the stability of anti-interference. This paper describes Mat lab simulation and FPGA implementation of the algorithm. Hardware experiments show that the algorithm can improve the performance of narrow-band interference suppression for the ordinary CDMA mobile phone about 25dB.