The invention relates to the technical field of computer block chains, and provides a data
interaction method based on block chain on-chain and off-chain coordination. The method comprises the following steps: firstly, constructing an on-chain and off-chain
collaborative interaction framework; when a user requests to write / update data, writing / modifying
original data in the off-chain
data center,extracting a data abstract from the
original data / to-be-modified data and signing, selecting a main node to construct a block and access a block chain, and then notifying other nodes to synchronize; when a user requests to inquire data, sending signatures to
verification nodes, the
verification nodes inquiring the on-chain data and
broadcasting the data, when more than half of the
verification nodes inquire the same data, selecting the main node, the main node inquiring the
original data from the off-chain
data center and extracting the data abstract, comparing the on-chain data and the off-chain data, if yes, returning the query permission of the user, and if not, informing the user that the data is damaged. According to the invention, the
data security and integrity can be ensured, and the speed is high when large data interaction is carried out.