Gamma Logging Tools work at a hot environment. Reasonable temperature compensation method is re- quired. Central processing unit of the total gamma probe is a single – channel analyzer. The usual method is to adjust the voltage of the photomultiplier tube according the temperature. But this method will enhance the dark current and noise of the photomultiplier, then SNR decreases. Therefore, a new temperature compensation method based on threshold control is proposed and appropriate circuits are designed. The test data at 20℃ and 150℃ pass T- test. The experiment proves that the method is good for the temperature compensation.