To stimulate the market vitality of distributed resources, the virtual power plant (VPP) has gradually transformed from a third-party profit organization to a service-oriented trading platform, and the transaction has shown a trend of decentralization. In this case, a new VPP trading mode is designed to solve the difficulties in multi-layer coordination and the lack of trust between market entities from the same layer. First, the consortium chain is combined with the multi-agent system to build a VPP internal transaction framework. In order to match the characteristic of the VPP with multi-layer market entities, the main-side chain governance structure is adopted to form data barriers and ensure the scalability of the transaction framework. Second, the existing consensus protocol is improved in accordance with the feature of VPP main chain, and the consensus reputation is introduced to maintain the operation efficiency of the blockchain. In order to improve the execution quality of distributed transactions and the VPP operation stability, the trading reputation closely related to the transaction result is introduced to constrain the trading behavior of aggregators, and a feasible bidding strategy is provided. Finally, the specific trading process of VPP based on the main-side chains is analyzed, and the main functions of smart contracts are designed in combination with internal market rules. The simulation results prove the feasibility and effectiveness of the proposed VPP trading mode.