The application provides a data sharing method, a source node, a destination node, and a data sharing system. The method comprises the following steps: a source node acquires transaction data from locally stored sensitive data, calculates the abstract information of the transaction data, releases the abstract information to a block chain system to enable the block chain system to store the abstract information and record the transfer action information of the transaction data, establishes a temporary data transmission channel to a destination node, and sends the transaction data to the destination node through the temporary data transmission channel; and the destination node acquires the abstract information released by the source node from the block chain system, receives the transaction data sent by the source node through the temporary data transmission channel between the destination node and the source node, verifies whether the received transaction data is consistent with the acquired abstract information, and sends transfer result information to the block chain system to enable the block chain system to record the transfer result information of the transaction data. The data sharing method, the source node, the destination node and the data sharing system are applicable to sharing of a large amount of sensitive data, and can improve the security of data transmission.