With the deepening of China’s electric system reform, the power market has gradually formed a pattern of diversi fied competition. Firstly, focused on the basic framework of block chain technology, combined with the construction needs of integrated purchase and sale of power platforms, the applicability of block chain is analyzed. Then, based on smart contract, the architecture and transaction mechanism of the platform are designed, which effectively guarantees the safety, openness and transparency of transactions. Finally, combined with the problems existing in the current purchase and sale process, the application prospects of the platform are analyzed.