With the continuous enrichment of workplace situation research, workplace interpersonal relationship is gradually favored by management science and psychology. As a unique embodiment of workplace interpersonal relationship, workplace friendship naturally becomes a research hotspot in the field of organization management. This study is based on the conservation of resource theory, and introduced relational energy as an agent and the sense of workplace social self-efficacy as a regulator, so as to explore the influence of workplace friendship on organizational citizenship behavior. After analyzing the data of 409 workers, the conclusion is as following: the workplace friendship has a positive influence on organizational citizenship behavior, the relational energy works as an agent between workplace friendship and organizational citizenship behavior, and workplace social self-efficacy up-regulates the direct effect of workplace friendship on organizational citizenship behavior.