Abstract: A service composition language is presented, which differs from many existing ones in its emphasis on enabling business users to visually “program”, from business viewpoint, their personalized applications on the basis of Web-based services. VINCA embodies an integrated approach to mediating between diverse, rapidly changing user requirements and composites of individual services scattered over Internet. The approach is targeted for the application scenarios that require Web-based services be quickly assembled and coordinated by non-computer professionals to fulfill certain spontaneous requirements. Design issues of VINCA and the approach to construct a VINCA program through a real scenario are illustrated.