It is difficult to neatly realize spatio temporal expression in traditional georelational data model for its complex organizing and storing on spatial data. But object relationship GIS simplify its complexity. Based on object relationship GIS

this paper puts forward the improved base state with amendments model

after analyzing some typical spatio temporal data model. This model takes the current state as base

and recorders the spatial objects' change procedure. All changes are reduced to "add" and "delete". Because taking the current state as base

it could avoid the spending for the frequently loading current map. Because its special method of recording change

it would randomly and rapidly generate spatial data of any past time on the support of SQL. In this paper

this model is also expatiated from three aspects: recovering snapshots

analyzing spatio temporal topology and reasoning the change of spatial object. These techniques are realized in an instance about land use change under the support of GeoMedia3 0. The successful test indicates that it is simple and facile to realize the improved base state with amendments model in object relationship GIS.