Data storage method and system based on block chain

The invention discloses a data storage method and system based on a block chain, and the method comprises the steps: receiving to-be-stored original metadata assets, carrying out the coding of each metadata asset in the original metadata assets, and obtaining a corresponding multi-dimensional coding identifier; each metadata asset and the corresponding coding identifier are stored in a decentralized block chain group, the block chain group comprises mutually verified nodes and child nodes connected with the nodes, each node stores one metadata asset, and the child node of the node stores the corresponding coding identifier; and according to the sensitive level of each metadata asset, performing hierarchical encryption on each node, and performing double-layer encryption on the nodes and the child nodes. By utilizing the embodiment of the invention, the problems of security, reliability and expansibility faced by the traditional metadata management can be solved by utilizing the characteristics of the block ch