Distributed storage method and device

The invention discloses a distributed storage method, a distributed storage device and a distributed storage system. A replica node receives an instruction transmitted by a center server for storing the content by the replica node, wherein the instruction for storing the content carries the information of the content; the replica node distributes a storage space for the content according to the information of the content and available storage space on the replica node; the replica node calculates a storage coefficient K of the content on the replica node, wherein the storage coefficient K is determined by the size of the content and the storage space distributed for the content; and the replica node randomly downloads and stores a data block divided by the content from the center server at a ratio of 1/K. Therefore, the storage efficiency is improved, the search and scheduling complexity of a client is reduced, and the network overhead is reduced.