美国建立之初法律制度主要移植于英国的普通法,判例法是美国法的主要形式。19世纪末期以来,美国联邦和州制定了大量的成文法,其中部分仅仅是对判例法的整理与汇编,如刑法、合同法,但是更多的则是开辟新的法律领域,如反垄断法、移民法、环境保护法、税法、公司法、证券法。作为一个普通法传统国家,美国走上成文立法道路的原因是多方面的,是法律文化、历史背景、现实需要等多种因素综合作用的结果:第一,英美、大陆两大法系相互融合的 At the beginning of the establishment of the United States, the legal system was mainly transplanted to common law in the United Kingdom. Case law was the main form of American law. Since the late 19th century, the United States and the United States have enacted a large number of written laws, some of which are merely collations and compilations of case law, such as criminal law and contract law, but more are opening up new areas of law such as antitrust law, Immigration Law, Environmental Protection Law, Tax Law, Company Law, Securities Law. As a traditional common law country, the United States embarks on a path of written legislation for many reasons. It is the result of a combination of factors such as legal culture, historical background and practical needs. First, the two major legal systems of Britain, the United States and the Mainland are integrated