Abstract: For weakly consolidated soft rock mechanical properties affected by the moisture content is big, and after the excavation roadway in weakly consolidated formation of the characteristics of big deformation of surrounding rock in Xiyi coal mine of Wujianfang mining area in Inner Mongolia as the engineering background, based on the weakly consolidated soft rock mechanics test, XRD diffraction analysis of minerals and liquid plastic limit determination results, moisture content of five groups of different strata of the numerical simulation model is established, the analysis of weak cementation formation water content are 2%, 5%, 10%, 15% and 18% when the stability of surrounding rock after excavation of roadway.The results show that the plastic thickness and volume of surrounding rock are almost unchanged when the aquifer content is lower (≤ 5%).With the increase of the aquifer content, the plastic thickness and volume of surrounding rock are approximately linearly increased.In the weakly consolidated strata, the maximum deformation of roadway surrounding rock occurs in the roof and floor, and gradually decreases when walking to the two sides of the roadway.The deformation of surrounding rock approximately increases linearly with the increase of formation moisture content, but the main deformation interval of surrounding rock is not significantly affected by formation moisture content.