At present, the New Entities (NEs) and the large-scale Electric Vehicle (EV) access to the electricity market to participate in the electricity trading under the constantly active environment, the transaction participants present a diversification trend. Based on the game theory, this paper analyzes the transaction mode and the new form of strategy selection in the electric power market by means of experimental calculation and simulation. Firstly, considering the factors such as geographical location, revenue and system loss, the static non-cooperative game model of EV groups, NEs and grid company is established. Then six NEs and two EV groups are used as examples, the Cooperative Coevolutionary Genetic Algorithm (CCGA) is used to solve the Nash equilibrium solution. The reasonable validity of the proposed method is verified by the numerical example, which provides a theoretical reference for the analysis of the role of EV groups and NEs in multi-party decision-making in electric power market.