In contrast to traditional business workflow, scientific workflow is mainly used to describe and control the execution of scientific experiment and research. Currently, scientific workflow technology is widely adopted by E-science application. Geographic information system (GIS) is a rapid development branch of spatial information domain, which is applied to E-science application especially gas network application. This paper analyzes the work process of gas network application based on GIS service and introduces a scientific workflow of spatial data processing. Then a modeling method of scientific workflow for gas network application based on GIS service is proposed. Furthermore, a prototype of gas network safety evaluation (GNSE) is developed for verifying the scientific workflow model. Our experimental results show that various services could be efficiently managed and controlled by using scientific workflow to evaluate gas network safety. Finally the conclusion and future work are included.