1. A method for reducing the dynamic false contour in the image of an alternating current plasma display, characterized by, comprising the following steps: dividing each frame image into multiple subfields; accounting the number and the probability of the dynamic false contour appeared in each frame image; and based on the result of the accounting, carrying out an optimized coding for the pixel data of each frame image, and if there is an error generated by the optimized coding, diffusing the error generated by the optimized coding into neighboring pixels.