APD (avalanche photodiode) is a very important photodetector, which is widely used in the fields of optical fiber communications and optical fiber sensors because of its high gain. But the thermo-performance of APD, which means that its gain is to vary with the temperature around, makes it difficult to be used more widely in the fields above. So the authors have done experiment research on the APD's thermo- performance and have solved this problem successfully. The thermo-performance of APD is systematically studied in this paper. The scheme of experiment system and experiment circuit which are used to measure to APD's temperature shift is introduced too, and the variation equation of its temperature shift is gained by linearizing the data got from our experiment. Moreover keeping the environment temperature constant and making compensation to the APD by adjusting the bias voltage are two key factors that should be carefully considered to research into the methods of compensating the effect of temperature shift. The two methods are discussed here too. And by these means the quite faint photoelectric signals, which has blent with the strong noise, can be picked up successfully. Our experiment conclusion is an important and valuable reference to using APD rightly and ensuring it to run steadily.