Abstract: In video coding standard H.264,motion search module occupies most of the time. In order to reduce the computational cost,the all-zero block detection method is introduced into motion search algorithm based on 4×4 integer transform.The proposed method can terminate the search for the most matching motion vector earlier by defining adaptive thresholds in the process of integer pixel and 1/2 pixel motion search.The simulations show that it can achieve significant complexity reduction of motion search while the coding efficiency loss is negligible.