Emergency calling This is my thesis english abstract, i wanna someone can help me to correct sentence. Extending my sincere gratitude to your favor. In order to assess the result of implementation of “ban on free plastic bags of china”, this thesis studied the situation of Chengdu, It has a very important reference to how to enhance the timeliness of environmental policy execution. Firstly, through "PEST Analysis model" detailed analysis of the background and motivation for government to introduce "ban on free plastic bags", then combed the follow-up initiatives of the relevant departments, deeply analysis the specific content of the ban, finding that the government's lag of the construction and weak the supervisory ability of the market is the crux of this problem. Combined the survey data of Chengdu, statistical analysis of those four variables (gender, age, level of education and income) how to effect on consumer behavior in plastic bags, combine with the theory of Victor Vroom's " Valence-Instrumentality-Expectancy theory " to make a discussion in depth with consumers utility function, and have explored a more deeply reasons about the hardship of the ban is that the utility generated based on environmental protection does not have timely feedback, Under the policy lack of implementation and environmental effects weakened feedback unsatisfactory reality, resulting in a lack of motivation on consumer's environmental behavior. Through the production and sale of plastic parts to cost-benefit analysis found that producers faced with a very serious moral risk , due to the lack of specific guidelines for supervision and punishment , and the amount of benefits from the production of substandard plastic behavior formed far much higher than the risk caused by illegal , making some manufacturers ignore the ban. Finally, based on the experience of the relevant policies in other countries and regions, and the status of the implementation of domestic, this thesis suggests that through the feedback of green taxes and related benefits of earmarking can greatly reduce the impact of poor timely feedback of environmental utility, which usually can weaken the motivation about environmental protection.