The long-term  effects of  market timing on the capital structure and the cumulative changes in leverage and their keeping  time were discussed. According to the empirical results, the external finance weight-average method of Baker and Wurgler was adjusted, and a measure method proposed. The outcomes indicated that the market timing would affect the capital structure in a long time, i.e. the capital structures of China listed corporations are influenced by historical stock prices, and this time length of the effect is five years.