In the development of power-grid GIS,there are varieties of files and many types of spatial database formats,and also a large number of grid spatio-temporal data are produced.In order to solve the problem of heterogeneous data and the application of spatio-temporal data in data exchange between different systems,data model and access technology of unified spatio-temporal power grid are proposed.Based on practical applications,this paper solves the use of heterogeneous data and temporal data from the data and access level by using the metadata concept and software plug-in model.It is proved by the application that the unified spatial data model and access technology can effectively reduce the workload of data preparation and system development,and can integrate the advantages of different data sources.