This study aims to analyse some college girl students’ exercise factors to prevent obesity using a health belief model. This study interviewed 500 college girl students from one university using an organized self-report type questionnaire from November 1 to 19, 2011 and a total of 472 responses except insincere responses were used for the final analysis. Of the 456 subjects, 56.3% (257) of the subjects had exercise intention to prevent obesity. As a logistic regression analysis, the following results were discovered: the more serious they were about obesity, the higher sensitivity, when they had information from the Internet networks, when they did regular exercise, and when their family or friends had suffering from obesity, significant relations with exercise intention to prevent obesity were found. However, perceived usefulness, self-perception on body figures, necessity of exercise, interests in health and self-efficacy which had significant relations in a simple analysis showed no significant relations with it. Based on the results above, the study discovered that regular exercise, the internet, obesity of family members or friends, perceived seriousness and sensitivity had relations with exercise intentions to prevent obesity. Therefore, it is suggested that intervention programs which can enhance care and sensitivity in developing obesity prevention education programs should be developed, and family members or friends should advise them to do regular exercise to prevent obesity and contents should be effectively distributed with uses of Internet networks.