In order to find out the water content of coal mine strata in the area with low mountain landform and large altitude drop in Yunnan-Guizhou Plateau, this paper used ground-air electromagnetic technology to carry out the detection of water content by ground operation in mountain coal mine strata. The detection work was carried out in Qinglong Anbao Coal Mine in Qianxinan Prefecture, Guizhou Province. The detection area was 1.56 km2. The water content of the coal seam roof and floor in the detection area was mainly explored, and a total of 32 low-resistance abnormal areas were delineated. By comparing with the known hydrogeological data and some drilling verifications, it was determined that the low-resistance abnormal area delineated by this detection was accurate and effective. The results proved the feasibility and effectiveness of using ground-air electromagnetic technology to detect the water content of strata in the low-mountain landform area of the plateau.