With the development of service-oriented computing environments, more and more Web services have become available. Service providers have to consider how to design composite services to meet requirements from various users. However, QoS of composite service is difficult to evaluate and predict due to the uncertainty and multiple metrics of QoS, which makes it necessary for user-centered design of composite services. Moreover, combining human services and Web services is becoming an important issue in service composition in cases that Web services cannot meet the requirements from users. Therefore, it is necessary to test the service composition environments for human-computer interaction and study human behaviors. In this paper, we address the above issues by proposing a participatory service design approach based on user-centered QoS considering a real-world case of field-based multi-language communication service design. To achieve this goal, we first describe the QoS model for service design considering users' requirements. Then, we propose the participatory service design process, consisting of service model refinement, participatory simulation, QoS evaluation and QoS data update. Finally, we use the field study of multi-language service design for Vietnamese agricultural knowledge communication to illustrate our proposed design methodology.