Abstract: In some extreme conditions such as the particle spectrum measurements in the space, the existing methods for neutron/gamma (n/γ) discrimination can not satisfy the requirements because of the long measurement time and the complicated conditions. A method for n/γ discrimination based on frequency comparison analysis (FCA) was introduced in this paper. The implementation mode of the analog circuits of FCA was also studied. The characteristics of FCA were studied by theoretical and experimental method. Compared with frequency gradient analysis (FGA), FCA can get better n/γ discrimination. The method can implement real-time discrimination by digital circuits as well as by simple band-pass filters. It shows great prospects for space radiation measurements and miniaturization of detection system.