Abstract: For more than 340 years of Tang dynasty and Wu Dai periods, there were 2828 persons demoted according to the record. In the temporal distribution of demotion, most of them lived in the midor lateTang Dynasty, and in the spatial distribution, the south, like Lingnan and Jiangnan which are remote and isolated, is the main area chosen as the demotion place especially in Tang Dynasty, which is the most worthy of studying.

Key words: demotion, timeandspace distribution, quantitative analysis, Tang dynasty and Wu Dai periods