This strong tendency is shown in the constant change of its value and goal orientation in the anti-trust law.

While advancing the enormous development of economy,industrial associations often implement restrictive practices such as price-fixing,market division,collective boycott,standardization activity and advertisement-limitation, all these practices constitute one type of restrictive agreements in nature and governed by anti-trust law.

Having developed for more than 100 years, America n anti-trust law, famous for its sternness, has formed a relatively perfect system, in which many important principles and systems have been set up through the cases of different periods.

With the development of antitrust economics and US economy, US antitrust law has been changing greatly.

America promulgated the earliest antitrust law - Sherman Act, and the judicial practices have also accumulated abundant cases law, whic.

The article use the Microsoft Case as a instance and use antitrust law of American as a brief introduction.

The change of judicial explanation for The Sherman Act shows the evolution of early antitrust decision in America, and the judicial process adapting to traditional democracy in industrial age.