With the widespread application of GIS,an increasing number of industries involved in GIS result in the appearance of multi-source heterogeneous data source.Due to the deficiencies of common methods of multi-source heterogeneous data integration,we put forward the integration of multi-source heterogeneous data based on middleware.GIS middleware integrates multiple data source driver and provides a unified interface to client GIS software,client GIS software can seamlessly integrate multi-source heterogeneous data without care about the specific format of spatial data,so we can fast and sequentially achieve to load multi-source data.This article introduces the working principle and concrete realization of model about the middleware,the technology of middleware has been successfully applied in the MapGIS platform and achieved the integration of multi-source heterogeneous data.