Abstract: Since Canada first made the antidumping measures in the world, 40 countries have made their antidumping laws. The antidumping laws practised in every country have obvious unreasonable points. First, the basic theory that dumping is harmful and on which antidumping laws are made is not so convincing. Second, the aim of antidumping is not definite. Third, in the operation of antidumping, the confirmation of the causality between the dumping and the injury is unfair and so is the treatment of non_market economies. The defects of antidumping are often utilized by some countries as international trade barriers. The problems appearing in the course of antidumping cannot be solved properly. It needs continuous negotiations among the members of WTO.