现实生活中习惯与制定法之间的冲突屡见不鲜,在某些领域,制定法成了一纸空文,脱离现实太远。而当事人往往采取其他社会规范来规避法律的适用,形成了实质上的法律多元化倾向,这些“其他社会规范”中最为常用的就是习惯。与此同时,民法典制定过程中,关于习惯是否成为法律的正式渊源也存在争议。本文试运用法律经济分析方法,对习惯法律化的成本和效益进行分析和比较,指出制定法与习惯的背离造成了法制资源的浪费,即用“反证法”来说明习惯的非法律化是不“经济”的,进而得出习惯应该法律化的结论。 Conflicts between the habit and the statute in real life are not uncommon. In some areas, the law has become a dead letter and far from reality. However, the parties often adopt other social norms to evade the application of law and form a substantive law diversification tendency. The most commonly used of these “other social norms” is the habit. In the meantime, there is also controversy over whether the custom is the formal source of law in the process of formulating civil code. This paper attempts to analyze and compare the costs and benefits of customary legalization by using the method of legal economy analysis and points out that the deviations of formulating laws and habits cause the waste of legal resources. Not “economy ”, and then come to the conclusion that the habit should be legalized.