Abstract: In order to study the effect of transient electromagnetic (TEM) on the detection of groundwater in thick coal seam mining area, groundwater in open pit coal mine in Junggar Basin of Xinjiang Autonomous Region is detected and verified from two aspects of numerical simulation and field measurement. First of all, the ground electricity section model of thick coal seam is set up based on the log curve, characteristics of TEM induction field are summed up by means of numerical simulation, theoretical detection results are analyzed. Secondly, TEM network is arranged according to the conditions of the field, acquisition parameters are set up according to the theoretical results, distribution and geological causes of groundwater are analyzed and deduced based on the real data processing results. Finally, abnormal area is exposed by ground drilling. The results show that TEM is adapted to the ground electric structure of the thick coal mine, location and scope of groundwater can be accurately reflected by TEM, and it is suitable for application in thick coal mine open pit.