System integration has been proposed as one of the characteristics which distinguish GIS from other information systems

but there are no appropriate methods to integrate with GIS and geography-model to perform flexible retrieval

development

and reuse mechanism.This paper makes an analysis on the modelbase system and the methodology of integration with GIS and geographic models

and proposes a service-oriented framework of distributed geography model integration.The goal of our research is to design a software framework

which can support distributed model construction

management and integration

with a concept of service and share.At first

we describe the model definition framework which defines model functions and data interfaces on the basis of the ideology of the document object model（DOM）

with more details of the flexible data definition mechanisms which can support dynamic data interchange and definition with XML. The framework can assist modeler to construct models for particular application domains and make the model features understood by GIS-developers more easily.Next

we describe the software structure with two components

the model server and the client

which are both based on the COM/DCOM technology: the model server

supporting RPC access

expands the function of traditional model base

provides the run-time supports and the integration environment into all kind of model programs

will facilitate the incorporation of legacy simulation models into the environment;the client component

composed of a set of COM components with DOM

provides the uniform pattern for integrating models and GIS application with the object-oriented application programming interface.Thus

this framework provides a basis for distributed model construction and sharing not only on the combination of GIS and model program

but also on other SDSS projects.