The invention provides a substation historical data unified storage method and system. The method comprises the steps that a proxy server is adopted to extract storage objects in relevant systems of substations; the storage objects are subjected to structured processing; and data obtained after structured processing is stored into a storage server cluster. Through the substation historical data unified storage method and system, permanent storage of historical data and files is realized, the limitation on storage capacity of a cache library is avoided, and the requirement of defect data statistical analysis of all manufacturer devices or equipment of all the substations in a region on mass data storage is met.