A robust optical flow algorithm for larger motion velocity and lager velocity change was presented.A novel gradient constraint equation was obtained through analyzing the error of temporal gradient.On the other hand

the anisotropic diffusion equation was introduced in the oriented smoothness constraint so that the computation of flow velocity in the motion discontinuity can be improved.According to these improvements

the multi-grid differential optical flow algorithm can not only alleviate the error propagation effect

but also adapt itself to larger motion velocity and lager velocity change.The experimental results have shown that the flow field of density 100% can not only be created by the algorithm proposed in this paper

but also be provided with good computation accuracy and robustness for lager motion velocity and lager velocity change.