The invention relates to a 3D rock mass point cloud registration method based on plane polygon matching. The method mainly comprises three stages (1), plane detection based on voxel multi-time regiongrowth; (2), PCA-based polygon matching; and (3), point cloud registration based on matching point pairs. The method comprises the following steps: firstly, dividing initial rock mass point cloud intovoxel grids, and extracting reliable growth units in each voxel by utilizing an area growth algorithm; Performing secondary growth based on the growth unit to obtain an initial plane set; for the initial plane set, remaining point clouds in neighborhoods around each plane grow, and a plane set in the rock mass point clouds is extracted; Secondly, extracting a polygon boundary of the plane point cloud, projecting a polygon to a two-dimensional plane by utilizing PCA, and carrying out polygon matching; the rock mass point cloud registration method based on the ICP algorithm is suitable for theregistration process of large-scene rock laser scanning point cloud, and the rock mass point cloud registration can be efficiently and accurately achieved.