Abstract: The achievements in environmental protection made by US are mainly contributed by its trinitarian environmental management system. Centered on environment, the system is composed of the following three parts: the comprehensive and complete environmental law system, which offers a powerful weaponry for environmental protection; the law enforcement agencies established on the basis of the National Environment Policy Act, which provides a powerful enforcer of the law; the operation mechanism combining prevention with penalty, which guarantees the effects of the law. It is due to the perfect combination of the above three factors that US has made tremendous achievements in environmental protection and it is regarded as the model of environmental protection in the Western World, its experience is to offer us important enlightenments for the construction of harmonious society.