In order to study the influence of PM2.5 particles on the detection performance of quantum interference radar, this article analyzes the relationship between the concentration of PM2.5 particles and the extinction coefficient under different particle sizes based on the spectral distribution function of PM2.5 particles and the Mie scattering theory. Then establish the influence model of PM2.5 particles on the detection distance and maximum detection error probability of quantum interference radar. The simulation results show that as the concentration of PM2.5 particles increases, the extinction coefficient of PM2.5 particles shows a gradually increasing trend; the energy of the detected photons is attenuated, resulting in a decrease in the transmission distance of the photons; when the energy of the emitted photons remains unchanged, The maximum detection error probability of quantum interference radar increases with the increase of PM2.5 particle concentration; when the PM2.5 particle concentration remains unchanged, the maximum detection error probability decreases gradually with the increase of the emitted photon energy. Therefore, the average number of emitted photons should be appropriately adjusted according to PM2.5 pollution in order to reduce the impact of PM2.5 atmospheric pollution on the detection performance of quantum interference radar.