1. A method for extending docbase management system functions, comprising: determining, by a docbase management system, extended data is in a format not supported by the docbase management system; parsing the extended data according to a preset format to obtain an extension identifier of the extended data when the extended data is stored as an extended object; or taking format information of the extended data as an identifier of the extended data when the extended data is stored as an image object; searching for an extended function module which matches the extension identifier of the extended data, wherein, the extended function module is compatible with a system extension interface in a the docbase management system; and invoking, through the system extension interface of the docbase management system, the extended function module found to process the extended data, wherein the extended function module comprises an enumeration interface and a function interface, the enumeration interface is configured to enumerate all interfaces of the extended function module and the function interface is configured to provide the function of processing the extended data; and invoking, through the system extension interface of the docbase management system, the determined extended function module to process the extended data comprises: invoking the enumeration interface of the determined extended function module, searching for the function interface configured to process the extended data in the extended function module; and invoking the function interface to process the extended data.