Abstract: Because the color of the key figures and the background area is too close, the color difference between the both is not obvious. The traditional algorithm is based on the different date of the gray scale of adjacent images to catch the key figures and it can't avoid the defects in which the color difference is not obvious bacause the color difference betwecn the key figures and the background area is too small, so it will reduce the precision in which the key character is captured automatically. A method based on the trajectory estimation algorithm for automatic acquisition of key figures was proposed in this paper to solve the above problem. The method extracts the characteristic parameters of the key figures,and predicts the critical movement trajectory of the key figures to complete the automatic capture of key figures.The experiments show that this algorithm enhances the accurate rate of key figures automation capture, and gets a satisfactory result

Key words: Key figures,Automatic capture,Trajectory estimate