This study attempts to analyze the effect of the decentralized environmental regulation. There have been debates whether devolution will contribute to improving or deteriorating local environmental quality. Panel data analysis is used in order to abstract the effect of decentralization. According to the results, the rate of inspection and of violation are decreasing after environmental decentralization, which is found to be a negative impact on environmental regulation. However, decentralization positively affects strong enforcement but, negatively weak enforcement. It is found that local governments have been trying to increase strict enforcement instead of increasing inspection. The analysis also shows that the effect of decentralized environmental regulation depends on local characteristics.