Abstract: Taking the mining of 201 working face of Wangjiata Coal Mine as the engineering background, the application of 3D laser scanning in the deformation monitoring and supporting of tunnel was studied. Under complex conditions in the mine, the effective scanning distance of the scanner is greatly reduced, which seriously affects the overall stitching accuracy. Therefore, this paper proposes a method for cloud registration of single test stations in two periods to obtain the deformation of the roof and floor of the roadway. The results show that: the cloud registration method at a single measurement site has millimeter accuracy and meets the requirements of underground tunnel deformation monitoring; in the monitoring area, the average subsidence of the roof is 14.70 mm, and the floor is 0.283 mm, and the deformation of tunnel shows non-uniform asymmetric characteristics; the maximum moving amount of the top and bottom plates and the thickness of the coal seam under the current support scheme are far less than the requirements of the specification. Actual investigation shows that after the mining of the 201 and adjacent 202 working faces, the tunnel has not collapsed, the support is too strong and the observation results are consistent with the actual situation. The mining support strength can be appropriately weakened.