The invention provides an electric power big data distributed storage system allowing N-5 storage mediums failing. The system comprises a distributed storage control and management unit, the distributed storage control and management unit is respectively connected with a [48,24,12] extended square residue code encoding processing unit, a write-in communication transmission channel, an a-row 48-column storage medium array, a read-out communication transmission channel and a [48,24,12] extended square residue code decoding processing unit, wherein the [48,24,12] extended square residue code encoding processing unit, the write-in communication transmission channel, the a-row 48-column storage medium array, the read-out communication transmission channel and the [48,24,12] extended square residue code decoding processing unit are connected in sequence. The [48,24,12] extended square residue code encoding and decoding technology and the Hash function abstract technology are adopted for the system, failure of any storage mediums of the number smaller than or equal to five is allowed, allowing N-5 failure is achieved, the problem about optimization of the balance among the storage capacity, the failure allowing capacity and the extensibility of the electric power big data cloud storage system is solved, data safety is protected, it is guaranteed that the data are private and complete to a certain extent, and thus construction and development of the electric power big data cloud storage system are boosted.