A method for cross-blockchain interaction, the method comprising: determining, by a blockchain node in a first blockchain, a message generated by a second contract in a second blockchain by using a cross-blockchain interaction end between the first blockchain and the second blockchain and by using a subscribing client corresponding to the blockchain node, the subscribing client being configured to maintain a plurality of message queues that are in a one-to-one correspondence with a plurality of blockchain nodes, to perform mapping to a corresponding blockchain node by using a message queue, comprising: initiating, by the blockchain node, a subscription request to the cross-blockchain interaction end, wherein the subscription request is used to indicate a subscription condition to the cross-blockchain interaction end, so that the cross-blockchain interaction end obtains the message that satisfies the subscription condition and is generated by the second contract, and adds the message to the message queue maintained by the subscribing client corresponding to the blockchain node; and determining, by the blockchain node, that the second contract has generated the message that satisfies the subscription condition when the message queue comprises the message that satisfies the subscription condition; performing, by the subscribing client, a verification on the message provided by the cross-blockchain interaction end by using a pre-anchored verification root, so as to provide the message to the blockchain node when the subscribing client determines that the message provided by the cross-blockchain interaction end is from the second blockchain; and calling, by the blockchain node, a first contract in the first blockchain to trigger a corresponding contract operation when the message generated by the second contract satisfies the subscription condition of the blockchain node. determining, by a blockchain node in a first blockchain, a message generated by a second contract in a second blockchain by using a cross-blockchain interaction end between the first blockchain and the second blockchain and by using a subscribing client corresponding to the blockchain node, the subscribing client being configured to maintain a plurality of message queues that are in a one-to-one correspondence with a plurality of blockchain nodes, to perform mapping to a corresponding blockchain node by using a message queue, comprising: initiating, by the blockchain node, a subscription request to the cross-blockchain interaction end, wherein the subscription request is used to indicate a subscription condition to the cross-blockchain interaction end, so that the cross-blockchain interaction end obtains the message that satisfies the subscription condition and is generated by the second contract, and adds the message to the message queue maintained by the subscribing client corresponding to the blockchain node; and determining, by the blockchain node, that the second contract has generated the message that satisfies the subscription condition when the message queue comprises the message that satisfies the subscription condition; initiating, by the blockchain node, a subscription request to the cross-blockchain interaction end, wherein the subscription request is used to indicate a subscription condition to the cross-blockchain interaction end, so that the cross-blockchain interaction end obtains the message that satisfies the subscription condition and is generated by the second contract, and adds the message to the message queue maintained by the subscribing client corresponding to the blockchain node; and determining, by the blockchain node, that the second contract has generated the message that satisfies the subscription condition when the message queue comprises the message that satisfies the subscription condition; performing, by the subscribing client, a verification on the message provided by the cross-blockchain interaction end by using a pre-anchored verification root, so as to provide the message to the blockchain node when the subscribing client determines that the message provided by the cross-blockchain interaction end is from the second blockchain; and calling, by the blockchain node, a first contract in the first blockchain to trigger a corresponding contract operation when the message generated by the second contract satisfies the subscription condition of the blockchain node.