The final purpose of well logging interpretation is to determine the original water saturation in reservoir，and the n define the properties of the reservoir fluids．Most of the current water saturation models are based on Archie formula．Volcanic reservoirs generally develop two types of pores，including fractures and matrix pores．If we simply use the Archie formula to calculate the water saturation，the value will be higher than the real value．This paper amended the Archie formula according to the characteristics of volcanic reservoirs，and then developed a double pores system based on oil—water identification method of volcanic reservoirs by introducing the double pores parameters．The application in Junggar Basin proves the good effect of this method．