The purpose of this study is a descriptive research study to analyze the factors that affect Christians' COVID-19 preventive behavior. The subjects of the study were 262 adult Christians, and the data collected were using SPSS 25.0 and AMOS 21.0 programs. As a result of the study, the subject's religious maturity level was 4.21 ± .55 points out of 5 points, COVID-19 stress was 2.86 ± .73 points out of 5 points, optimism bias was 2.94 ± 1.26 points out of 7 points, and COVID-19 preventive health behavior was 4 points. The total score was 3.54 ± .44 points. As a result of the correlation analysis of the subject's religious maturity, COVID-19 stress, optimistic bias, and COVID-19 preventive health behaviors, COVID-19 preventive health behaviors were faith maturity (r=.156, p=.012), COVID-19 stress (r=.216, There was a positive correlation with optimism bias (r=174, p=.005). In conclusion, it can be said that the higher the religious maturity, the higher the COVID-19 stress, and the higher the optimistic bias, the better the preventive health behavior of COVID-19, and the explanatory power of the overall model was 9.4%. In the post-COVID-19 era, it is necessary to develop educational programs that can prevent infectious diseases and promote health in the community.