The invention discloses a distributed data storage system and method based on a blockchain. The method comprises: inputting a data content into a data storage module by a data inputting module, and using a hash algorithm to calculate an extract of the data content to store on the blockchain; receiving the data content by the data storage module, retrieving the extract corresponding to the data content, and storing the data content that is consistent with the extract; and when data querying is carried out, finding a stored queried data content by the data storage module, retrieving an extract corresponding to the data content, and returning the queried data content that is consistent with the corresponding extract to a querying node. According to the system and method, the blockchain is used in the information storage system, a Root-privilege administrator does not exist, no one can arbitrarily modify an information content without being detected, and reliable management and secure sharing of information are realized; and the blockchain is not directly used to store the data content, only the extract obtained by calculating by using the hash algorithm is stored, the amount of storage on the blockchain is reduced, low efficiency of the blockchain is avoided, and the practicality is improved.