United States has extended the extraterritorial application of U.S. Antitrust Law in 1990s. First, The U.S. Federal Supreme Court declared in Hartford Fire Insurance Co. v. California that the extraterritorial application of U.S. Antitrust Law is according to Effect Doctrine. Therefore, U.S. Antirust Division and FTC will continue to base their assertions of juridiction on the test of direct, substantial and foreseeable effects on U.S. interests. Second, U.S. Antitrust Law apply to foreign conduct that such conduct has direct, substantial and reasonably foreseeable effect on U.S. domestic or import commerce and export commerce. Third, United States has extended the extraterritorial application of U.S. Antitrust Law on international licensing contract or international merger. Forth, United States impose criminal responsbility of U.S. Antitrust Law on the foreign anticompetitive conduct. Therefore, our government and industries must consider the corresponding stratigies against the extension of the extraterritorial application of U.S. Antitrust Law.