The invention discloses a three-dimensional detection method for the defects of a sealing surface. The three-dimensional detection method comprises the following steps: obtaining pictures with scratches on the sealing surface; obtaining the length and the initial width of each scratch according to the pictures with the scratches; determining a scanning route according to the initial width; planning a scanning track according to the scanning route; and scanning the scratches along the scanning track, thus determining the depth and the final width of each scratch. Compared with the prior art, the three-dimensional detection method for the defects of the sealing surface has the advantages that the pictures with the scratches on the sealing surface are obtained so as to avoid a leak detection condition of the small scratches; then the length and the initial width of each scratch are obtained according to the pictures, the scanning route is determined according to the initial width, the scanning track is further planted according to the scanning route, and finally, the scratches are scanned along the scanning track so as to determine the depth and the final width of each scratch, so as to realize the three-dimensional detection of the defects of the sealing surface. Meanwhile, the measurement precision is improved and the size quantification detection on the three-dimensional defects of the sealing surface is realized.