The invention relates to a multi-frame range image automatic registration method. (1) Any two frames of range images are registered through using SIFT characteristics, and the correctness of a result is judged. First, the SIFT characteristics of the two frames of the range images are calculated, corresponding points are bidirectionally crossly matched, then polar line constraint is calculated by a RANSAC algorithm, error matching is filtered, then the two frames of the range images are accurately registered through using an ICP algorithm, and the correctness of a result is judged. (2) a cycle space of a model diagram is researched, and a global consistent registration result is calculated. First, a derived cycle basis of the model diagram is calculated, an adjacency relational graph of the derived cycle basis is built, then a group basis of the consistent cycle space is calculated, and further a consistent registration result is obtained. The method can effectively increase the research speed of the cycle space, and an exponential time complexity can be increased to a line time complexity in an ideal condition. (3) the consistency of a cycle is judged, and the consistency of the registration result in the cycle is judged by a judgment method of relative differences. The invention can reliably automatically register multi-frame range images, through researching consistent cycles, error registration is taken out, thereby obtaining consistent registration results.