The H.264/AVC video coding standard uses 7 variable block sizes ranging from 16?16 to 4?4 in interframe coding. The motion estimation with 7 modes needs very high computational complexity. To reduce the complexity of ME module in H.264, we propose a new and fast motion-estimation algorithm based on partial block distortion for sorted significant features including bit-plane and absolute difference of means (ADM). The partial distortion searching (PDS) algorithm, from top-to-bottom line matching scan, is a popular method for fast full search (FSS) in H.264. When the proposed algorithm is combined with the sub-block PDS (proposed-PDS), it can find the same motion vectors as FSS. Furthermore, when the proposed algorithm is combined with the normalized PDS (proposed-NPDS), it can obtain relatively accurate motion vectors with a large reduced computational load. Simulation results show that the proposed-PDS method requires about 90% of the computation needed by the FSS in H.264 without any loss of R-D performance, and the proposed-NPDS requires only about 68% of the computation needed by the FSS with the R-D performance very close to FFS.