By the analysis of the signal transfer model of a complementary metal oxide semiconductor (CMOS) camera, the transfer function model of signals and noises in this CMOS camera is builded and the linear relationship between the output image signal and the image noise of this camera is deduced. The testing system of the performance parameters of this camera is established, and the conversion gain, the maximum signal-to-noise ratio (SNR) and the dark noise in time domain of this CMOS camera are tested. The test value is compared with the index value, and the results show that, the performance parameters of this camera can be can accurately tested with this proposed test method, which is suitable for the test of the photoelectric parameters of most types of cameras.