Avalanche photodiode(APD)can be used as frequency modulation continuous wave(FMCW ) radar laser photoelectric detector andalso realize the photoelectric mixing function. In order to study whetherAPD is influenced by its temperature in the progress of photoelectric mixing，mixing modelsare constructed accord-ing to the definition of mixing peSNR model. Based on APD gainthat mixing performance of APDrformancemodel andmixing performance models，experience research is adopted tois influenced by its temperature. The experimental results and theoreticalshow that the worseand the poorer is itsrising of temperatureis the heat dissipation of APD itself

namelymixing performance，the mixing efficiencyof APD.thehigher is the temperature，the gain ismixing signal-to-noise ratio decreasemixingexploreanalysissmallerwith theand known gain model，including mixing efficiency model and