The effective implementation of environmental regulations is vital for constructing China's ecological civilization. From the perspective of local government competition, this paper constructs an evolutionary game model for the interaction of Chinese local government environmental regulation strategy. Then, the mechanism of local government environmental regulation competition and its influencing factors are explored. The results show that local governments are more inclined to relax environmental regulations when the losses of strengthening environmental regulations increase, which results in the race to the bottom in environmental regulation. However, environmental regulatory competition among local governments will be affected by externalities. In addition, adequate supervision by the superior government and an increase in the weight of environmental indicators in the performance appraisal system are conducive to the race to the top in environmental regulation among local governments. These research results can provide policy enlightenment for the central government to strengthen environmental supervision and win the battle against pollution.