It is difficult to generally apply web services to an enterprise IT environment, because it only supports basic connection technologies such as SOAP, WSDL, and UDDI. A method to support dynamic composition of the tasks is necessary. To achieve this, a workflow standard that enables definition and control of process units is necessary. Among such standards, RPEL4WS(Business Process Execution Language for Web Service) is an important flow language that connects and controls different tasks and systems. When designing a workflow based on BPEL4WS, the functions that need to be supported are enabling detail design of processes including ones with dynamic properties, and the user should be able to easily and intuitively visualize the workflow. This paper provides the development of a Web service based workflow design tool for logically dividing the design and using a metaphor that is easy for the user to visualize the workflow. This will enable users to easily create and orchestrate business processes and lower the design complexity.