Abstract: Abstract：The stope with thin bedrock in loose aquifer was prone to frame crushing and water discharge accidents, In order to ensure the safe mining of thin bedrock stope, based on the geological conditions of 1512 (3) stope in Gubei Coal Mine, Comprehensive theoretical analysis, mechanical experiment and industrial test, The laws of roof structure, core mechanical properties and stope pressure behavior before and after ground pre grouting reinforcement in weathered zone of thin bedrock stope were studied, In order to analyze the effect of grouting reinforcement. The results show that:The effective diffusion range of ground grouting in weathered zone was more than 15m, After grouting, the cementation, compactness, impermeability and stability of weathered rock were enhanced, The average shear strength of core was increased by 40.6%, The overall bearing capacity of the roof was significantly improved, Combined with the hydraulic support with high working resistance, the safe mining of working face was realized.