The invention relates to a service method and a service device for converting multi-source data. The device comprises a data source interface module, a data importing module, a data cleaning module, a data converting module, a consolidated data structure module, a consolidated storage type module, a consolidated exporting interface module and a flexible export setting module. The service method and the service device for converting the multi-source data have the following advantages: 1) an independent device is specially responsible for operations, such as data exchange of various advanced application systems and various basic service systems in a power dispatching center, thereby improving efficiency of data conversion, and ensuring correctness and timeliness of the data conversion; 2) each advanced application system only needs to acquire data from a data conversion service device, thereby saving complicated workload of data conversion, and saving development cost and maintenance cost; and 3) the advanced application system is separated from data conversion, thereby saving hardware resource, and improving operating efficiency and operating stability of the application system.