本文主要檢討過去學者對秦漢刑期的看法，並據江陵張家山漢簡〈二年律令〉部分及其它文獻與出土資料，從思想和實際存在的律令兩層次，重新論證漢文帝以前之秦漢刑法已存在刑期。文帝改革的意義並不在建立刑期，而在使原本存在的刑期制體系化和固定化。

Based on the newly published legal texts unearthed at Zhangjia-shan, Jiangling, Hubei, this paper attempts to argue that a system of terms of servitude appeared in the Qin and Early Han China. The idea and system of terms of servitude took shape gradually in the periods of Spring and Autumn and Warring-States. The melting-down of the feudal system of ranks and the needs of manpower of the time contributed to its appearance. The main task in the legal reform of the Emperor Wen was not, as many scholars assert, to start a system of terms of servitude, but to make it more systematic.