Transaction processing method and device based on block chain

The invention provides a transaction processing method and device based on a block chain, and relates to the technical field of block chains. The method comprises the following steps: receiving first transaction information; querying a corresponding discount smart contract according to the merchant identifier, the third-party payment platform identifier and the card issuer identifier to obtain a discount amount, and returning second transaction information; obtaining details of receivable service charges according to the transaction amount, the discount amount and the receipt service charge collection rule; broadcasting an acquiring service charge confirmation request to confirm the service charge receivable details; if transaction payment confirmation information and receivable service fee confirmation information corresponding to the first transaction information are received, verifying the receivable service fee confirmation information; and if it is known that the service fee collection confirmation infor