Due to the cross-boundary characteristicof inter-organizational information systems (IOS), its usage is affected by inter-organizational relationships (IORs), which plays an even more important role in China.This paper develops a conceptual model of the influence of IORs on IOS usage and supply chain performance. Based on organizational learning theory, the paper dividespatterns of IOS usage into IOS use for exploitation and exploration. And the paper puts forward an innovative perspective to evaluatesupply chain performance from efficiency and flexibility dimensions. Using a sample of 151 Chinese companies, structural equation modeling (SEM) is applied to empirically testing thehypotheses.The finding indicates that inter-organizational trust has significant positive influence on IOS usage, while power and cooperative norms do not. And IOS usage plays a positive role in promoting supply chain performance and exploitative usage is better for the efficiency promotion.Therefore, much attention ought to be paid to nurtureinter-organizational trust rather than power to promote IOS usage and supply chain performance.