The development of new energy vehicles (NEVs) cannot be separated from the support of subsidy policies. However, the effectiveness of different subsidy policies remains to be verified. To investigate a more effective way of NEV subsidy and maximize the effect of subsidy policies, this study proposes two subsidy strategies, namely, consistent subsidy and adaptive subsidy, and constructs a network-based evolutionary game model for NEV diffusion. The effects of different subsidy policies are then comprehensively evaluated from the supply and demand sides, and their internal influence mechanisms are further investigated. Results show that: 1) from the supply side, subsidy for both policy achieves the highest NEV diffusion, but subsidy for enterprises is more efficient; 2) from the demand side, NEV diffusion increases NEV sales in the same proportion. Surprisingly, the increase in NEV diffusion rate benefits traditional vehicle manufacturers by expanding their average market demand; 3) from the cost-benefit analysis, the adaptive subsidy is more efficient than consistent subsidy; 4) The higher the initial benefits of NEV enterprises, the higher the level of NEV diffusion. The government should implement the adaptive subsidy and focus on providing subsidies to NEV enterprises to increase the NEV diffusion rate and achieve efficient resource allocation.
