The invention belongs to the field of 3D detection and measurement, and particularly relates to a
point cloud fusion method and
system based on a symmetry plane. The problems of
point cloud layering, mutual overlapping and the like generated when multiple groups of point clouds are fused are solved. The method comprises the following steps: 1, defining two groups of point clouds needing to be fused, namely point clouds {pi, j} and point clouds {qm, n}; 2, calculating a tangent plane L1 of the
point cloud {pi, j} at the point pi, j and a tangent plane L2 of the point cloud {qm, n} at the point qm, n; 3, calculating an average tangent plane of the tangent plane L1 and the tangent plane L2; 4, calculating space coordinates of a mean value point r'i, j of the point p'i, j and the point q'm, n, wherein the point p'i,j is a point after median filtering of the point pi, j, and the point q'm, n is a point after median filtering of the point qm, n; 5, calculating a projection point coordinate of the point r'i, j on the average tangent plane, namely a coordinate si, j of a point after the point pi, j and the point qm, n are fused; and 6, fusing all points in the point cloud {pi, j} and the point cloud {qm, n} by using the processes from the step 2 to the step 5 to obtain a fused point cloud {si, j}. Through the process, the layering and overlapping phenomena of the point cloud can be eliminated.