This paper investigates the issues when several complementary geospatial web services are chained to be a customized application process. This paper proposes a conceptual framework and a data structure, called Service Chain Graph (SCG), to describe the geospatial web service integration and the dynamic construction of service chaining process. A set of dynamic structural transformation rules is given to model the dynamic process of service chaining. Implementation issues are discussed and a prototype system is briefly presented for integration of several distributed, heterogeneous geospatial data services based on the model proposed by this paper.