According to bamboo slips in Qin Dynasty, "tuli" refers to such prison sentences as chengdan, lichenqie, guixin and baican, which could be bought and sold by the government, with the character of criminal slavery.

By means of the AHP theory, the essay divides the comprehensive evaluation indexes of urban transit planning into five categories, respectively including the evaluation on technique, economic benefit, engineering construction, social benefit and environmental influence, and finally, confirms the evaluation index and index subjection degree of each of the five categories.