Abstract: The geological structure and rock formation water conditions in the northwestern region are different from those in the eastern region. To study the mine water in the thick loose layer and sand layer geological structure of Yulin mining area, this paper took Yuandatan Coal Mine as the engineering background. The hydrogeological characteristics of the mine were analyzed. The amount of water in the wellbore was calculated. The mine water inflow was evaluated. The results showed that the fractures in the rock formation are rich. The overlying loose aquifer and sandstone aquifer were thick, which poses a threat to the safe use of the wellbore. The water inflow from the main inclined shaft, the auxiliary inclined shaft, the inlet shaft and the return shaft shaft were 243m3/h, 388m3/h, 1409m3/h and 1388m3/h, respectively. Yuan Datan Coal Mine had a large amount of water in the wellbore of Yuyang Coal Mine and Yushuwan Coal Mine. The amount of water in the intake shaft was particularly significant, and waterproof measures should be strengthened during the mining process..