Data model is a representation of data and its relation. It is consi-dered very important in database design. In constrast to alphanumerical data

spati- al data is characterised by its large magnitude and complexity.Therefore

it is ofsignificance to do research on spatial data model.Most commericial GISes are basedon relational data model.However

its drawbacks on representing spatial entitiesand their interrelations have led to the separation of graphic database and attributedatabase. In order to overcome this problem

extended relational data model andobject-oriented data model are explored.This paper introduces these three data mo-dels and their corresponding GIS architecture

analyses their pros and cons

and pre- sents the relation between spatial data model and GIS architecture.