摘要:Protecting user interests is one of the most important public sector responsibilities in PPP (public-private partnership) projects. However, user interests could be damaged by poor project performance. Therefore, this study focuses on the protection of user interests in PPP projects and analyzes the relationships among relational norms, project performance, and user interests in PPP projects. A questionnaire survey is conducted to collect the opinions of professionals from the public sector and private sector. Upon analyzing 109 valid questionnaires, the results demonstrate that the relational norms between the public sector and private sector have a positive effect on project performance, and project performance has a positive relationship on user interests. Moreover, project performance has a positive mediating effect on the relationships between relational norms and user interests. This finding can provide a theoretical foundation and suggest practical measures to help the public sector better protect user interests in PPP projects.