Abstract: The experimental research was made on the surface potential characteristics of coal measures rock samples under uniaxial compression, and the laws and reasons of surface potential were discussed. The results showed that the surface potential produced in the sample failure process under uniaxial compression. When the load changed suddenly, the surface potential would change as well. On the whole, the change trends of surface potential and load were same, which were significant correlation, even highly correlation. The surface potential mainly came from the free charge accumulating on the surface of sample in the internal failure process. The free charge produced during electronic emission from stress concentration and charge separation during crack growth. The piezoelectric effect caused by the composition of a certain amount of quartzes also played an important role for surface potential. The change laws of surface potential could reflect the destruction of coal measures rock samples under the load, which provided a new way for the rock stability monitoring.