The thermal fatigue crack propagation behavior of WC-8Co cemented carbide in different quenching agents was investigated. The pH of the aqueous solutions varied between 5.2, 7.4 and 8.8. This study was in the temperature range of 650 ℃ to 10 ℃ by using V-notch plate specimens.The results have shown that a corrosive environment has a strong influence on the thermal fatigue crack propagation behavior of the material test. Acidic and alkali environment can reduce the thermal fatigue crack initial life and increase the crack propagation rate. In addition, in the neutral environment, the thermal fatigue crack propagates along the WC / Co phase boundary, and in acidic and alkali environment, the crack propagates through the pits and the large size of the reunion things.