China has severe environmental problems and at the same time well-designed environmental rules, only the implementation by governments is to be blamed. To solve similar puzzles, western countries have introduced private regulators and studied private regulation for decades. However, the private regulators playing an important role in Chinese environmental regulation seem to have been forgotten by both the Chinese and the western academics. The Environmental Impact Assessment (EIA) institutions, which have the main role in evaluating projects, are the oldest and most typical example of Chinese private regulators in environmental regulation. This research seeks to make up for the absence of academic work on Chinese private regulators by examining the evaluation style of EIA institutions with empirical methodologies.