Purpose: This study aims to investigate the mediating effect of grit in the relationship between body image and health promotion lifestyle for nursing students. It was implemented to present basic data for the development of educational programs to establish the health promotion lifestyle of nursing students. Methods: The participants of this study were 169 nursing students in three universities in G City, J Province. Data were descriptive statistics, t-test, ANOVA, Pearson correlation analysis. Also mediation analysis was performed according to the Baron and Kenny method and Sobel test. Results: Health promotion lifestyle is positively correlated with body image(r=.53, p<.001), grit (r=.37, p<.001), and body image is positively correlated with grit(r=.33, p<.001). The grit showed a partial mediating effect between the body image and the health promotion lifestyle(Z=3.21, p<.001), the positive the body image(β=.46, p<.001), the higher the grit(β=.22, p<.001), the healthier the health. The level of health promotion lifestyle increased, and the explanatory power to explain the health promotion lifestyle was 33%. Conclusion: Therefore, in order to improve the health promoting lifestyle level of nursing students, it is important to change their perception so that they can view their body image positively. In addition, it suggests that nursing students need to cultivate grit so that they can continuously pay attention to and strive for their health promotion lifestyle.