本文对唐代以来历朝法典的“户婚律”中,禁止表亲中兄弟姊妹通婚条款的传承及流变做了翔实的考察,认为法律如果与当时的社会环境及民情风俗相悖,则丧失可操作性;从这条缺少操作性的律条在法典中存在了一千多年的事实,进而认为在皇权专制时代,因为“重刑轻民”的传统,法律调节民事的能力是有限的,民事纠纷大多靠民事习惯法自行化解。 This article has made a detailed investigation of the inheritance and change of the prohibition of the marriage clause between brothers and sisters of the cousins ​​in the “law of marriage and family marriage” of the dynasties in the Dynasties since the Tang Dynasty, believing that if the law runs counter to the prevailing social environment and customs, Operability; from the lack of operational law in the Code there are more than a thousand years of fact, and then that in the era of imperial autocracy, because of “tion of light people” tradition, the ability of the law to regulate civil affairs is limited Most of the civil disputes are resolved by civil customary law.