中文摘要：

伴随芝加哥学派、后芝加哥学派的兴起和发展，以及在国际市场上越来越受到迅速崛起的欧洲与日本强大的竞争压力，20世纪80年代以来，美国政府逐步放弃了由哈佛学派创立于罗斯福新政时期，并指导美国反垄断法实践长达半个世纪的结构主义理论，改行效率优先原则，大大放松了对企业兼并的控制，推动了美国产业市场的寡头化发展和企业国际竞争力的提升。美国作为现代市场经济的代表，研究其兼并指导准则的演变，对处于经济转型期的我国建立企业兼并规制具有十分重要的借鉴意义。

英文摘要：

With the rise and development of Chicago school, post Chicago school, and in the international market more by the rapid rise of Europe and Japan the strong competition pressure, American government gradually abandoned founded by Harvard School in Roosevelt period in twentieth Century 80 years, guided American anti-monopoly law practice for over half a century of structuralism theory, diverted the principle of giving priority to efficiency, and greatly relaxed the control on the merger of enterprises, promoted the industry market USA oligarchic development and the enterprise＇s international competitiveness. American as the representative of the modern market economy, the evolution of the merger guidelines, has very important reference significance to the merger regulation established in the period of economic transformation in China.