Instead of joining most scholars’ debates on whether the sex between Wang Jiajih and Mr. Yi is the reason of her betrayal in Eileen Chang’s “Lust, Caution”, this paper offers another possible explanation by focusing on the influence of Wang’s loss of virginity and thus turns “lust/caution” controversy into “chaste/ lubricant” discussion. Part 1 explicates how the comrades’ gazing at Wang’s losing her virginity can be an alienating force and thus an important cause of their disruption. Part 2 examines how “sacrificing the virgin” ideas under patriarchy influence the comrades’ decision, which leads to Wang’s feeling betrayed and pushed to Mr. Yi. Part 3 explains Wang’ s multiple identities as a heroine/whore/femme fatale and her chaste/lubricant dilemma, giving related examples from other fictions. Part 4 analyses Eileen Chang ‘s “passive beauty” ideas, providing an explanation of Wang’s “loving the wrong guy” and comparing Wang Jiaji and Yin Bao-yien (heroine of another of Chang’s short stories). Part 5 discusses Wang’s high self-consciousness as a beauty and how it leads to her confusion between playing a role and the real life. Moreover, feeling others’ jealousy toward her also leads to her alienation. Finally Part 6 explicates how Ang Lee’s interpretation separates the cause-and-effect relations of Wang’s losing virginity and her betrayal and thus deduces Eileen Chang’s art of fiction. However, Chang’s invention of the plot of “losing virginity” and her sophisticated handling of this theme show what the movie version seriously missed.