Due to insufficient consideration of various motion orientations in Merge mode, reducing the prediction accuracy of versatile video coding (VVC) interframe prediction, a VVCbased multidirection refinement Merge mode optimization algorithm is proposed. Based on the analysis of Merge mode with motion vector difference, the algorithm first adjusts the step size selection range and adds multiple search directions, then adaptively selects the motion compensation method of chroma block according to the step size. And finally selects the optimal motion vector information according to the ratedistortion cost criterion. The results show that, comparing with VTM120 reference model, the BDrate of Y, U and V components decreases by 057%, 062% and 025% in lowdelay Pframe configuration, respectively. In the random access configuration, the Y component of BDrate decreases by 027%, the U component only increases by 011%, and the V component decreases by 004%, which effectively improves the coding performance of Merge mode.