Abstract: In order to solve the technical problem of soft rock engineering deterioration with expansive water-rich in Inner Mongolia Shanghaimiao Mining Co., Ltd., the experiment of the influence of water content on the mechanical properties of rock was carried out. It is found that the physical and mechanical properties of rock are the internal cause of engineering deterioration, while water is the external cause. Based on this, the concepts of “soft water treatment first” and “large water prevention and control small water management” are proposed, some technical measures are taken, such as drainage and mining, bottom arch water-proof, funnel water-connecting, deep-digging water nest, wide-spread awning, hose diversion, centralized drainage, concrete shotcrete sealing, etc. The engineering practice shows that the convergence rate of roadway section decreases from 40.752% to 10.673%, the recovery efficiency increases from 81,000 t/mon to 463,000 t/mon, and the tunneling efficiency increases from 190.6 m/month to 520.3 m/month.