Abstract: An arbitrary nuclear spectrum pulse signal generator based on FPGA was presented in this paper. With this pulse signal generator based on 32 bit random number generator, output pulse signal could meet probability density function of the reference spectrum in pulse amplitude by sampling from reference spectrum in pulse amplitude. In the meanwhile, the system could finish interval segmentation of 1 024 for the time of pulse appearing. Then the appearance probability of pulse signal in different intervals and the average time between time intervals were calculated. By random sampling, the output pulse signal could meet the law of exponential distribution in time. The practical test result shows that the pulse which is outputted by this signal generator can meet the Poisson distribution in count rate, and can meet probability density function of the reference spectrum in pulse amplitude as well. The system noise is less than 2.86 mV, and the output pulse count rate could be adjusted, which meet the law of nuclear pulse signal.