Relationship management capability is a significant factor in promoting a firm’s service innovation performance. Although there is a rich body of study on the role of relationship management capability in performance of firms, scant attention has been paid to the joint effect of relationship learning and competitive intensity. Drawing on the service innovation, network capability and relationship learning theories, this paper establishes a relevant conceptual model, and adopts a hierarchical regression analysis to examine the model with a data set of 298 firms from China. Results show that relationship management capability positively affects the service innovation performance of firms; however, relationship learning partially negatively moderates the relationship between relationship management capability and service innovation performance. The three-way interaction effects of relationship management capability, relationship learning and competitive intensity are partially significant. This paper extends the existing literature on service innovation, network capabilities and relational learning in a service-centered economy. The findings further clarify the process mechanism of the impact of relational management capabilities on enterprise service innovation performance, and should help enterprises utilize relational learning and competitive intensity to break through resource limitations rapidly. The paper offers some enlightenment on promoting service innovation.