Objective: To determine the factors influencing unprotected sexual behavior among college students，so as to provide the reference and basis for better sex safety education in college. Methods: From March to August, 2022, 3 188 college students from three universities, namely "double first class" universities, ordinary public undergraduate universities and ordinary private universities, were selected by stratified random cluster sampling method. Cognitive Style Graphic Test, Adolescent Health related Risk Behavior Questionnaire and deographic information questionnaire were used to investigate. Results: Cognitive style and unprotected sexual behavior were positively correlated ( r=0.13, P <0.05). A total of 18.23% ( n =314) of participants reported engaging in unprotected sexual behavior. Binary Logistic regression analysis of participants grouped by cognitive style indicated major factors affecting unprotected sexual behavior among college students. In the field independence group, male students, senior students, and those with frequent romantic encounters (1, 2, and ≥3 times) had more unprotected sexual behavior ( OR =1.28, 1.79, 1.35, 1.68 , 1.84, P <0.05). Four major factors were associated with unprotected sexual behavior in the field independence group: junior and senior college students, those that study liberal arts, urban student source, and those with frequent romantic encounters (1,2 and ≥3 times) ( OR =1.91, 2.01, 1.26, 1.40, 1.46, 1.78, 1.99, P<0.05). Conclusion College students unprotected sexual behavior is associated with multiple factors. Cognitive style is an important reference variable. The factors influencing this behavior have differing effects according to the different cognitive styles among college students.