Objective: To explore periodontal health knowledge and behavior among adolescents aged 12-15 years in Henan Province so as to provide scientific basis for oral health care. Methods: According to the basic methods of the Fourth National Oral Health Survey, 3 786 school adolescents, aged 12-15 years, were selected from 12 middle schools in two district and two country in Henan by multi-stage stratified equal capacity random sampling. Oral examination and a questionnaire survey were performed among these students. Results: The rate of periodontal health was 6.08%, the prevalence of gingival bleeding in these adolescents was 93.92%, its calculus existence was 90.99%. The rate of brushing teeth was 77.79%. However, the rate of brushing teeth twice or more per day was 17.56%, the rate of using fluoride toothpaste was 4.57%. The rate of periodontal health of adolescents who brushing teeth, using fluoride toothpaste were higher than adolescents who did not brush teeth, did not use fluoride toothpaste (χ2=10.81, 5.96, P<0.05). The recognition of oral care knowledge was 62.31%; except for "bacteria can cause dental caries", the awareness rate of other related periodontal diseases is more than 50.00%. Conclusion The status of periodontal health among adolescents aged 12-15 in Henan Province was not optimistic. Adolescents are lake of knowledge and health behavior towards periodontal health, The promotion of adolescents’s oral health education should be strengthened.