A
data processing method based on a
blockchain. The method, which is executed by means of a
computer device that maintains a
consensus node on a second
blockchain, comprises: acquiring a cross-chain message submitted by means of a forwarding service device, and acquiring a
blockchain identifier carried in the cross-chain message, wherein the cross-chain message is associated with cross-chain
transaction data stored in a first blockchain (S101); acquiring, from a second blockchain corresponding to the blockchain identifier, block Merkle information corresponding to the first blockchain, and acquiring, from a block
Merkle tree represented by the block Merkle information, a Merkle proof set corresponding to the cross-chain message, wherein the Merkle proof set includes node information of some nodes in the block
Merkle tree, and the verifiable height of the block Merkle information in the first blockchain is greater than or equal to the block height of a block where the cross-chain
transaction data indicated by the cross-chain message is located in the first blockchain (S102); performing validity
verification on the cross-chain message according to the Merkle proof set and the block Merkle information, so as to obtain a cross-chain
verification result corresponding to the cross-chain message (S103); and if the cross-chain
verification result indicates that the verification is successful, acquiring a transaction execution result corresponding to the cross-chain message, and storing the transaction execution result in the second blockchain (S104).