Abstract: To solve the difficult problem of soft rock tunnel support in Liuyuanzi Coal Mine and reduce the times of tunnel repairs, the rock strength of roof and two sides of the tunnel was tested by in-situ testing method. The content of clay minerals and expansive clay minerals in floor rocks were measured by X-ray diffractometer, the mechanical parameters and mineral compositions of tunnel were mastered. A new type of slurry with non-shrinkage, non-condensable water, good fluidity, fast solidification time and high compressive strength was injected into surrounding rocks, and anchor net spray and anchor rope is used to the repaired tunnel at the same time. Through more than 9 months of deformation observation, the maximum displacement of the two sides of the tunnel is 10 mm, and the displacement of the roof and floor is 40 mm, which meets the requirements of the safe operation of the belt tunnel.