Abstract: Wanglou coal mine in Shandong province has been affected by water inrush from the mine since its construction.Liuguantun fault runs through the middle of Wanglou mine field, and the water inflow from multiple working faces near the fault are extremely high, judging whether the fault conducts water, and then leaving a reasonable width of the fault prevention water-proof coal rock pillar is essential to prevent the water inrush from the fault in Wanglou coal mine and reduce the mine water inflow.This paper takes Liuguantun fault water-proof coal and rock pillar retaining in 27309 working face of Wanglou coal mine as an example, evaluate the scalability of the fault to determine the water conductivity of the fault from both lateral and vertical directions through methods such as lithology opposed mapping method, SGR fault gouge ratio method, and section positive pressure discrimination.According to the evaluation results, an applicable formula is selected to calculate the width of the water-proof coal pillar in Liuguantun fault, and combined with the analysis of the previous working faces water production, the size of the water-proof coal pillar in Liuguantun fault is comprehensively determined.The results show that Liuguantun fault near the 27309 working face is a water-conducting fault, and it is comprehensively determined that the width of the water-proof coal pillar of the fault should be 140 m.It can ensure that the working face does not conduct water, but also can recover coal resources to the maximum extent, which is extremely important for the safe production of the entire mine.