Effective relationship management is an important source of competitive advantage for enterprises. With the increasing importance of platform ecosystem in digital economy， it is an important topic to better understand of the multilateral relationship faced by complementors in platform ecosystem. Based on this， using the method of literature research， it firstly traced the evolution of the formation of the multilateral relationship faced by complementors in the platform ecosystem. Then， based on the process of value creation， delivery and capture， it sorted out the content and management of the relationship faced by complementor between the platform owner， other complementors， and users. Finally， the future research framework was constructed according to the logic of “antecedent-behavior-result-context”. It not only discusses the multilateral relationship from the micro perspective， but also explores the interactive environment of complementors in the platform ecosystem， which improves the research perspective of platform ecosystem as well as lays a foundation for further exploring the behavioral logic of complementors.