The literature has suggested that interpersonal guanxi between boundary spanners is conducive to promoting partner firms‘ extra-role behavior (ERB),but it has neglected the double-edged effects of guanxi. This research, by untangling guanxi into expressive guanxi and instrumental guanxi, explores whether the different dimensions of guanxi have different effects on partner firms' ERB.Analyzing the data collected from 650 managers of retailers in household appliance industry of China? and testing the research hypothesis by multiple¯level regression method?? The study finds that expressive guanxi between boundary spanners positively affects partner firms' ERB, but the instrumental guanxi negatively affects partner firms' ERB. Moreover, when a firm's relative dependence increases, the positive effect of expressive guanxi on partner firms' ERB increase, but the negative effect of instrumental guanxi on ERB decrease. Additionally, market uncertainty weakens the negative effect of instrumental guanxi on partner firms' ERB. This study deepens the research on the antecedents of inter-organizational ERB by revealing the important question of which and when personal guanxi promotes (or inhibits) inter-organizational ERB, it also enriches the understanding of the situational conditions that affect the double-edged sword effect of personal guanxi.