Objective The purpose of the study is to investigate and analyze the periodontal health care knowledge and behavior of college freshmen in Luzhou city，and to provide a scientific basis for oral health prevention for college students. Methods Adopting the method of random cluster sampling，441 freshmen from two universities in Luzhou city were investigated. Results 79.1% of freshmen brushed their teeth twice or more per day and 20.2% of freshmen had the habit of flossing. 60.5% of freshmen visited dentists，while only 9.0% of freshmen visited a dentist for oral health prevention. 64.2% of freshmen knew that gingival bleeding was abnormal，while only 39.2% of freshmen knew that gingival bleeding needs treatment. 4.5% of freshmen，mainly male students，had the habit of smoking. 4.3%，22.2%，53.7%，16.3% and 3.4% of freshmen considered their oral condition as very good，good，fair，bad and very bad respectively. Conclusion Freshmen don’t know enough about periodontal disease and their health care behavior is not standard. Gender，place of birth and dental visit are the factors that affect the knowledge and behavior of periodontal health care of freshmen.