Lewis—Randall规则是化学热力学中一个重要规则,不少物理化学教科书都提到它,文献[1]认为该规则适用于实际气体的理想溶液,即其混合性质满足理想气体混合性质的气态溶液,但都来对该规则的适用条件进行必要的讨论。本文由维利方程推演Lewis—Randall规则,从维利系数的物理意义阐述理想化气体混合物的微观特征及Lewis—Randall规则的适用条件。 The Lewis-Randall rule is an important rule in chemical thermodynamics. Many textbooks refer to it. Literature [1] considers that this rule is applicable to the ideal solution of real gas, that is, the gaseous solution whose mixing property meets the ideal gas mixing property, But all necessary to discuss the application of the rules. In this paper, the Lewis-Randall rule is derived from the Willy’s equation. The microscopic features of the idealized gas mixture and the applicable conditions of the Lewis-Randall rule are expounded from the physical meaning of the Willy’s coefficient.