This specification describes techniques for performing cross-blockchain interactions. One example method includes generating, by a blockchain node in a first blockchain, a subscription request to a cross-chain interaction end between the first blockchain and a second blockchain. The blockchain node can then obtain a message from the second blockchain based on the subscription request, and subsequently perform an operation related to the obtained message. In some instances, the message obtained by the blockchain node is a message that is published in the second blockchain and satisfies subscription conditions of the blockchain node.