listed companies which had income smoothingwith voluntary accounting policy changes during 1998-2002 were chosen as sample. The authors studied on the incentives of the income smoothing of listed companies by the paired match of sample firms and the control sample firms, and then thngh the mean test, Wilcoxon sign rank test and Logistic regression models. The results show that the income smoothing has a positive correlation with the firm size, price restriction and compensation contracts. It is also characterized by income increase.