Abstract: In the study of particle detectors,based on digital signal processing,since the particle detectors for the relatively low energy of the incident particle, the noise characteristic of the circuit impact on the ultimate performance of the circuit is very large.Particle detector readout circuit noise model created in MATLAB Simulink environment,including thermal noise,shot noise and low-frequency noise.Simulation of the three types of the power spectral density of the noise on the basis of the model in this article a good fit to the three noise power spectral density function curve simulation results with the theoretical analysis of the curve obtained with the relationship of the input signal frequency changes. Further, the results are consistent with the simulation results with noise sequence of the three noise power spectral density function curve obtained by the power spectrum calculating,in order to verify the generated noise sequence model is correct.