Plasma displays represent gray levels by pulse number modulation technique, which results in unfavorable dynamic false contour (DFC) on moving images. The paper proposes a method to reduce the DFC by optimizing the sub-field sequence. Sub-fields are arranged according to the descending order of the weight-modulated sub-field histogram. This sub-field arrangement has a quasi-stretched-out property. Simulation results show that the method provides a good solution for both reducing the DFC and improving the gray level expression.