Abstract: Aiming at the unknown source of underground water gushing in Tianchi coal mine in Shanxi Province, this paper carried out underground monitoring and sampling laboratory test analysis through field tracing test, and found out the hydraulic connectivity between the surface hydrologic hole area and the underground water outlet point. At the same time, the high density resistivity method and the induced polarization method were used to test the surface boundary of the mining area before and after the rainstorm, and the abnormal water gushing channel was inferred by comparing the inversion results. The results show that the overall trend of chloride ion concentration at the outlet point of the main well increases slowly, but the change range is small, about 20 mg/L. The chloride ion concentration at the outlet point of the track roadway is stable, and the variation range is about 10 mg/L. Both on-site and indoor test results showed that the overall conductivity of the water samples at the two outlet points showed a gradual decline trend, and no wave peak appeared. Therefore, it is concluded that there is no obvious hydraulic relationship between the surface hydrologic hole area and the two underground water discharge points. It is speculated that the reason is that the water source of the underground outlet has another source, or the high waterproof curtain formed by grouting in the early stage blocked the tracer solution and could not reach the underground outlet. The comparison between the high density resistivity method and the high density induced polarization method before and after heavy rain shows that the coal seam resistivity difference before and after rain is small, which means that the water insulation performance of the grouting section is good. There are three low-resistance anomalies in the section, and the resistivity is further reduced after rain. Combined with the tracer test, it is determined that the YC-1 channel has little influence on the mine water inflow, and the water seepage of YC-2 and YC-3 should be further identified in the later stage.