Abstract: In order to determine the safety coal pillar types of 12th mining area. In this paper, according to the hydrogeology and geological exploration data of the east wing of the 12th mining distract located at Zhaojiazhai Mine, combined pumping test data and Theis formula, we calculate aquifer parameters, and research thickness distribution of loose layer and flat and vertical characteristics of the loose aquifer and aquifuge layers, especially the hydrological parameters at the bottom of the loose aquifer. The results showed that the thickness of the loose layer in this area is obviously controlled by the ancient terrain;The vertical has a multilayer composite structure and the continuity of the aquifer is poor. The bottom aquifer is weak to moderate and the mining level of water body at the bottom of the loose aquifer is grade II and part is gradeⅠ, which provides a scientific basis for designing safety coal and rock pillars types.