In the processing of digital video it is commonly needed to wipe out blotches in the image. Motion estimation is a basic step for this end. Sometimes, motion vectors may be far away from the true motion vector in the blotch area. Existing algorithms consider only spatial relations among motion vectors. These techniques are unsatisfactory to remove blotches completely. To improve this point, a method for estimating motion vectors considering the spatial and temporal relations among motion vectors is developed. At the same time, relations among hierarchical blocks are also considered in this paper. The result shows that the method is effective.