Based on 87 texts of professional discourse within the editing domain, this study explores the issue of professional authority construction expressed by editors in professional discourse. Editorial authority, legitimized as a form of power, guides editors to establish legitimacy through professional knowledge, ethical standards, and occupational norms, forming a contractual agreement with society. In the practice of editing, editors apply their knowledge and wisdom to make informed judgments and decisions. The institutional guarantees, decision-making authority, and influence provided to editors, coupled with the cultivation of professional knowledge and skills through self-discipline and the support and trust of relevant communities, collectively construct the professional authority of editors. The three legitimacy mechanisms—cognitive legitimacy, moral legitimacy, and consensus legitimacy—shape the social acceptance foundation of editorial authority, revealing the intricate social mechanisms that constitute editorial authority.