Abstract: Blockchain is an emerging shared database technology. Due to its decentralization， transparency and fairness， it has been researched and applied in various fields. On the basis of the traditional carbon emission trading mechanism， a credit scoring mechanism is introduced to define the transaction priority value （PV）， and then the carbon emission trading blockchain network model （BENT） is proposed. It is worth mentioning that a smart contract model （SC） combined with the carbon emission trading mechanism is established in this model， thus achieving automatic measurement of carbon emission rights and currency. Finally， simulations of three power companies with different carbon emission right requirements show that the BENT model can better reflect the carbon emission trading needs of market participants， and ensure the safe storage and interaction of information through blockchain technology and the scoring mechanism is conducive to fair and equitable operation of the market， further constraining market participants and promoting the goal of achieving carbon emission reduction.

Key words: carbon emission trade, blockchain, credit scoring mechanism, transaction priority value, smart contract