A data-access system, adapted to a plurality of Cloud storage providers, including a processing module, an access module and a storage module. The processing module receives a file, and obtains a dismantling rule according to file information. The processing module further dismantles the file into a plurality of sub-files according to a storage signal and the dismantling rule. The access module respectively detects the status of the connection of the Cloud storage providers, and the sub-files are stored to at least two of the Cloud storage providers according to the connections statuses. The storage module stores the dismantling rule and the storage records correspond to the sub-files.