For unreasonable attention model, limitations of optical estimation and noise, the result of existing computational method of visual motion attention sometimes can not reflect real motion attention information for video scene of motion complex. A new computational method of visual motion attention is suggested. In the method, motion attention model is firstly built according to the mechanism of attention. Then, the visual motion attention is computed on basis of variable size block motion estimation. Finally, the final salience map come from the fusion of multi-scale motion attention salience map. The experimental results also show the calculation result of this method is better than that of the existing method.