In a service-oriented geoscientific research environment, individual geospatial services must be chained together as scientific workflows to solve a complex geospatial problem. The emergence of various visual workflow designers, such as Taverna, GridNexus, Kepler, greatly facilitates the construction of geoscientific workflows. However, existing scientific workflow tools are mainly desktop-based. The emergence of Web 2.0 technology has shown promise to develop a the browser-based scientific workflow designer, which can bring rich experiences to users. This paper describes the design and implementation of a geoscientific workflow tool by integrating the Web 2.0 and geoprocessing services. The design of workflows is based on a three-phase procedure: process modeling, process instantiation, and workflow execution. The approach and experience provide valuable references for future development of Web-based geoscientific workflow systems.