Transaction processing method and system based on block chain

The invention discloses a transaction processing method and system based on a block chain, and relates to the technical field of transaction processing. One specific embodiment of the method comprisesthe steps that an acquiring bank generates a signed first hash value according to transaction request information and first state information and broadcasts the signed first hash value to a block chain; the issuing bank generates a signed second hash value according to the authorization information, the second state information and the signed first hash value, and broadcasts the signed second hash value to the blockchain; the acquiring bank performs clearing according to the authorization information and the transaction request information to obtain first clearing information, generates a signed third hash value according to the first clearing information, the third state information and the signed second hash value, and broadcasts the signed third hash value to the blockchain; and the issuing bank performs clear