In China, where appearance is highly valued, the number of men and women undergoing plastic surgery is increasing. For the healthy development of medical aesthetics, research from a cosmetic perspective—including social culture, mental health, and personal choice—is necessary. Therefore, this study examined the concepts of beauty, appearance-related stress, and the acceptance of plastic surgery and petit plastic surgery among men and women in southwest China. For this study, data were collected from 245 participants surveyed between November 15 and December 20, 2024, and analyzed using SPSS WIN 21.0. The analysis methods included factor analysis, reliability verification, frequency analysis, descriptive statistics, t-tests, correlation analysis, and multiple regression analysis to test differences and examine relationships among various factors. As a results of the study, First, women scored higher than men in gender-specific beauty needs, appearance-related stress, and acceptance of petit plastic surgery, with significant differences confirmed. Second, beauty needs and appearance-related stress showed a significant correlation with the acceptance of both plastic surgery and petit plastic surgery. Third, the greater the perceived effect of medical aesthetics and appearance-related stress, the higher the social acceptance of plastic surgery. Fourth, the greater the perceived effect of medical aesthetics, appearance orientation, and immersion, the higher the social acceptance of petit plastic surgery. The study concluded that the desire for beauty and stress related to appearance are important factors influencing the acceptance of plastic surgery and petit plastic surgery. Moreover, a stronger desire for beauty and a greater perceived effect of medical treatment corresponded to higher social acceptance of surgery. To alleviate social expectations and pressure regarding appearance based on gender, the study suggested the need to address gender role stereotypes and promote critical awareness of appearance-oriented values. Therefore, it advocated for rational social perceptions of plastic surgery and petit plastic surgery and emphasized the importance of psychological approaches and aesthetic value education as marketing strategies in the medical beauty industry.