Abstract: The power spectrum density analysis method is incorporated in the analysis of ²⁵²Cf fission neutron random signal.An actual spectrum density analytic system for ²⁵²Cf neutron signals is constructed,which combines the pulse-time collector and PC processor.The system can on-line acquire the time series data of neutron pulses（3 channels） based on FPGA and DSP,and then implement the data processing,corre-lation calculation,FFT calculation and power spectrum density calculation on PC.A reduced power spectrum algorithm is designed simultaneously.The system can exactly detect the ²⁵²Cf neutron pulse and effectively obtain the results of characteristic parameters such as correlation function and power spectrum density,and then provide the effective preparation for the dynamic parameters measurement of ²⁵²Cf neutron source or reactor.