This study used system dynamics to draw a stock-and-flow diagram for new-energy vehicles. A new approach called a "reverse even grey model (1,1)" was developed, and SPSS was used to process the data. Furthermore, the synthetic degree of incidence was used to examine the feasibility of the model. Four hypothetical scenarios for new-energy vehicles development were analyzed to find the ideal solution for China. These analyses showed the following: (1) Cadmium has certain environmental risks. At present, battery recycling is the main problem related to new-energy vehicles in China. (2) Total energy consumption is influenced by the dominant vehicle type in the market (new-energy vehicles and traditional fuel vehicles). (3) The government's purchase policy can promote sales of new-energy vehicles, but its effect is limited. Finally, (4) a "green paradox" effect exists in new-energy vehicles in China. Based on the findings, suggestions are made for the reasonable development of new-energy vehicles in China. Hence, this research has certain health and environmental benefits.