The invention relates to an electric vehicle Internet scene applied to a local energy aggregator and an electric vehicle for carrying out demand response, and a method for jointly solving the problemsof how to protect the safety of transaction information and the privacy of both parties of the transaction, how to design an incentive mechanism, and how to predict the private information of the electric vehicle. We propose a transaction method based on coalition block chain, which protects the security of transaction information and the privacy of both parties, and reduces the cost of consensusprocess in the process of building a transaction information block. In order to encourage electric vehicles to participate in demand response, we propose an incentive-compatible demand response mechanism based on contract theory modeling. In order to maximize social welfare, the contract is tailored to the unique characteristics of each type of electric vehicles. The optimization problem is solved by using the iterative convex-concave programming algorithm. In order to predict the private information of electric vehicles, we derive the probability distribution of EV type by exploring the computationally intelligent state-of-charge (SoC) estimation technology. Finally, the relationship among social welfare, EV type, incentive, emission power and SoC estimation errors is illustrated by numerical results.