Purpose: This study was conducted to provide basic data for college students living in the Seoul metropolitan area to prevent the spread of infectious diseases and explore countermeasures by identifying the degree of difference with anxiety, stress, and preventive health behavior before and after the COVID-19 vaccination. Methods: Data were collected from the subjects of the study, 192 college students aged 19 to 29 who completed the COVID-19 vaccination in the Seoul metropolitan area. The data were analyzed with the correlation, paired t-test, and independent t-test using the SPSS 27.0. Results: Preventive health behavior, health anxiety, and stress showed the positive correlation before and after the COVID-19 vaccination among the college students. After the COVID-19 vaccination, COVID-19 related stress including fear of infection (d=-0.11±0.09), and difficulty in social distancing (d=-0.21±0.08), and health behavior (d=-0.06±0.44) decreased compared to before the vaccination. Conclusion: Health education and health policies are required to continue preventive health behavior even after the vaccination.