For extending the life cycle of products and satisfying the further requirement of customers, product-service system (PSS), an integration of products and services is considered as a promising solution. However, for PSS design, customers’ expectations on the purchased product could be changed due to the development of technology and fashion. For this reason, the life of value might be exhausted before the real life of a product. Although there are some existing upgrade plans or maintenance plans for PSS design, it is found to be risky for PSS firms to provide the mentioned plans that are threatened by various uncertain events. Thus, to achieve an upgradable PSS, it is extremely essential to propose a method to identify the requirement for upgradability based on the perspective of customers. To achieve this aim, this paper has developed a method includes four steps. In step one, a set of definitions is provided to clarify the upgradability of PSS. In step 2, this study utilizes a PEST-OT matrix to analyze the driver of the future development. Step3 uses a persona-based explorative scenario building method to identify the characteristic of targeted customer and build a scenario of interaction between customer and PSS in a future scenario. Step 4 provides a requirement transformation method to transform the requirement into receiver state parameter (RSP). After that, the RSP is transformed into detailed product characteristics (PChs) and service characteristics (SChs). To verify the effectiveness, a case study of shared furniture is used. The result of the case study shows this method could work effectively in a Business-to-Customer business.