Traditional narratives on Qin and Han legal history are relatively obscure, fragmentary, and sometimes unreliable. Although Chinese, Japanese and western scholars had endeavoured to depict a relatively comprehensive picture of Qin and Han legal system, there were limited prospects for substantive analysis and clarification of legal terminology until the discovery of the legal manuscripts unearthed from Shuihudi in the 1970s and Zhangjiashan in 1980s. This essay provides an overview of current scholarship, beginning with an introduction to the legal materials from Shuihudi and Longgang. The third part summarizes the contents of the texts from Zhangjiashan the Qin slips in the possession of the Yuelu Academy. The remainder of this article offers a preliminary reconstruction of the penal system and criminal procedures of the Qin and Han eras, mainly on the basis of the Yuelu Academy and Liye manuscripts. The Qin penal system had at least seven degrees of punishment, with twenty-three further ramified levels. In addition, there were at least four procedures in criminal proceedings: (1) accusation/denunciation; (2) interrogation; (3) trial; (4) sentencing. The essay also translates and discusses several newly excavated legal documents related to these procedures.