determining a target block height according to a local log file of the backward node for synchronizing blockchain data of the blockchain system, wherein the target block height is used to indicate a processing progress of the blockchain data, and the blockchain data comprises data and a block height corresponding to the data;

sending a data synchronization request to a target node based on the target block height, wherein the data synchronization request comprises the target block height; and

writing, in response to receiving update data sent by the target node, the update data into a local storage area of the backward node, wherein a block height corresponding to the update data is greater than the target block height,

wherein the sending a data synchronization request to a target node based on the target block height, comprises:

executing the local log file to generate blockchain data corresponding to the local log file, wherein a block height corresponding to the data in the blockchain data corresponding to the local log file is smaller than or equal to the target block height; and

sending, in response to determining that the executing of the local log file is completed, the data synchronization request to the target node.