Objective：To explore the psychological factors influencing seasickness in different individuals, so as to provide guidelines for prevention and treatment of seasickness from psychological perspective. Methods： Medical undergraduate students （n=124） were subjected to the following tests before training on the sea： rod and frame apparatus, motion sickness history questionnaire, seasickness self-efficacy scale, body vigilance scale, EPQ, and state-trait anxiety inventory. The total number of valid questionnaires was 123. During sailing the seasickness state of students was assessed by Graybiel＇s diagnostic criteria based on their seasickness symptoms and signs. Results： Among the 123 students 75 had seasickness and 48 did not have. Single factor analysis showed that motion sickness history and seasickness self-efficacy were statistically significant（P〈0. 001）. Binary logistic regression analysis also showed motion sickness history and seasickness self-efficacy were statistically significant （P〈 0.05）, indicating they were the important psychological factors influencing the development of seasickness. Conclusion： Motion sickness history and seasickness self-efficacy may provide important guidelines for psychological training on anti- seasickness.[著者文摘]