ObjectiveTo investigate knowledge, attitude and behavior towards healthcareassociated infection (HAI) among medical students of different school years and majors, and evaluate the teaching method on the education about HAI and occupational precaution. MethodsA survey was conducted among medical students of school year 2008-2010 during their initial period of clinical practice with a simple random sampling method by specifically designed questionnaires. Results448 medical students were investigated, 421 (93.97%) effective questionnaires were received. With regard to grasping HAI knowledge, the percentage of correct answer was statistically different among students of different majors (χ2=1.62×104,P<0.05), nursing students ranked first(78.28%),and students of rehabilitation major ranked last(60.90%); the percentage of correct answer was also statistically different among students of different school years (χ2=14.62,P<0.05),students of school year 2008 ranked first (75.51%), and 2010 ranked last(70.63%). With regard to attitude, more than 90% of students realized the importance of HAI prevention and occupational precaution, there was no statistical difference in attitude among all school years (H=1.39, P>0.05), but the difference in attitude among students of different majors was significant (H=86.70, P<0.05), nursing students scored highest, 50% of whom scored >74,medical laboratory students ranked last,50% of whom scored >66. With regard to behavior, 54.46% of the students often/always showed behavior of HAI prevention and occupational precaution, the scores were statistically different among students of different school years (H=36.49,P＜0.05) and majors (H=180.32,P＜0.05),in terms of school year,50% of students of year 2008 and 2009 scored >60 and ≤55 respectively， in terms of major, nursing student got the highest average score（63.76±10.11), 8year program students scored lowest (47.94±14.35).ConclusionDuring the initial period of clinical practice, medical students demonstrate a satisfactory level of knowledge and attitude towards HAI, but their behavior need to be improved; it’s necessary to perform education about HAI knowledge as soon as possible, enhance the awareness of HAI, and improve occupational precaution among medical students, so as to reduce the occupational exposure and cross infection in hospital during the internship period.