The present invention relates to an accurate registration method of multi-frame depth image. Said method includes the following steps: (1), judging boundary point, noise point and isolated point so as to remove point whose noise is large; (2), selecting reference point in overlay area of different depth images, creating correspondent point buffer zone for every reference point so as to search correspondent point in buffer zone; and (3), adopting iteration method to progressively optimize whole registration accuracy. Said invention also provides the concrete steps of said iteration method.