Abstract: In the context of certification industry, the impacts of the service quality of certification agencies on relationship quality are studied. Based on four dimensions of service quality (process service capability, process interactive quality, potential service capability, and outcome quality) and three dimensions of relationship quality (cooperativity, adaptability and atmosphere of connection), the model of impacts of service quality of certification agencies on relationship quality is constructed. An empirical study involving 721 enterprises shows that process service capability and outcome quality have significant influence on the relationship quality, while process interactive quality and potential service capability have not significant impact on the relationship quality. Finally, some recommendations are proposed for certification agencies in order to improve their service quality and remain good relationship with their clients.