中國中古時期，封建與諸侯是重要的關鍵詞。西晉開建五等之際，特地設立〈諸侯律〉，以強調諸侯的重要性。然而至西晉以降，除北周時期外，歷代皆不再採用〈諸侯律〉，其原因仍須進一步的分析。本文從律文篇目繼承關係、諸侯相關法律條文、諸侯實際處罰案例等方向，探討中國中古諸侯與〈諸侯律〉的內容，並重建〈諸侯律〉在中古時期具有的政治意義。中古時期與諸侯相關的法律條文，多為諸侯各項抵免罪刑的規定，未見諸侯犯罪行為與處罰的條文。正由於諸侯名義上地位崇高，因此不可隨意用律法限制與處罰諸侯，對諸侯的處分實為政治或禮制問題，而非法律問題。西晉設立〈諸侯律〉的目的，並非處罰諸侯，而是為了強調諸侯的特殊性，以及凸顯諸侯之上的皇帝權力。〈諸侯律〉並非必然存在的法律篇目，其存廢對於中古法制體系幾無任何影響。因此，〈諸侯律〉僅是西晉、北周復古改制的點綴，無法成為長久的法律規範。

The feudalism of Western Zhou was an important ideal in political system of Medieval China. The law of feudal lords was created by Western Jin Dynasty, but it was abandoned by Dynasties except North Zhou Dynasty. This paper focuses on the analysis of Law of feudal lords, which bornd and disappeared in Medieval China. This paper also discusses the legislative background of Law of feudal lords. Those feudal lords had Lofty status, so they shouldn't became the object to be punished. The disposal of feudal lords was political issues, rather than legal issues. The birth of the law of feudal lords, not only showed that Western Jin government tried to ”rebuilding” the feudal system of Western Zhou, but also constrainted the power of the emperor. The law of feudal lords was only for embellishment in medieval China.