Abstract: At present, renewable energy generation in China is growing rapidly. Green power trading is widely concerned as a market-oriented means to promote the power accomodation of renewable energy. With the gradual liberalization of the participation for green power in market trading, the trading system is facing the dual challenges of trust and efficiency. It is urgent to optimize the mechanism design and build a credible and efficient trading environment to meet the credibility and timeliness needs of largescale multi-agent trading. Therefore, a green power trading system based on the blockchain is constructed. First, this paper proposes the generation, trading and traceability mechanism of the green power consumption certificate. Then, the overall architecture system based on the blockchain is designed, and a green power trading system with core capabilities such as efficient consensus, on-chain trading and identity authentication is built. Finally, through the system test and the applications of green power trading and green power consumption certificate trading, the completeness and practicability of the system are verified.