A new optical flow estimation method for color image sequence is proposed,from a new point of view,the probability and simplicity of using the concept of geometric algebra to analyse color optical flow is discussed in detail. Color image sequence is presented by multivectors in geometric algebra,it is proved that if meet the constrained conditions for color optical flow analysis,a multivector instead of multichannel image processing method can be used to represent the continued distribution of images to expand the measurement range. then a new optical flow constraint equation and its solution in geometric algebra domain was deduced based on color invariance under motion,The experimental results of several synthesized and natural image sequences show that this algorithm can improve the ability of color optical flow estimation in different conditions greatly.