Abstract: Aiming at the high-risk of sewage treatment projects operation and the difficulty of control illegal emission,four kinds of computational experiment scenarios are constructed based on whether fluctuations between discharge information and sewage disposal price or not.Then the mechanism of formation of pollution charge,polluters.behaviors,government regulation and public restriction are built,simult aneity, some indexes,such as to lerance degree,demand elasticity,are chosen to analysis the changes of behaviors and nature of enterprises or residences under the triple restriction from economic pressure,social influence and governmental regulation.Finally,computational experiment is used to simulate the dynamic changing of sewage treatment project operation and polluters.behavior in four kinds of situations.The result shows that reasonable static pricing strategy superior to dynamic operator-leading pricing strategy,dynamic external environment lead to high risk for both sewage treatment project operation and illegal emission control,neither pure market-driven pricing regimenor governmental regulation can preventillegal emission or improve residents to save water and reduce emission,the profi-tpur suiting nature of firms and operators will fail to fulfill the objective.

Key words: sewage treatment projects, computational experiment, polluters behavior, tolerance degree