Objective To study the natural progress of different degree chronic periodontitis and its association with IL-1B-511 genetic polymorphisms. Methods 100 subjects with chronic periodontitis were selected and exam-ined at baselined and in the 6 month and in 1 year on attatchment loss at 6 sites of each tooth. DNA samples were obtained with buccal swabbing technique and were further analyzed for IL-1B-511 genotype polymorphisms using PCR-RFLP-based method in all subjects. Results The mean AL increases were 1.43 mm within 1 year. Among 100 subjects, 16 patients with moderate progression（0 mm＜AL increase/a year≤1.0 mm）, 84 patients with rapid progres- sion of periodontal disease（AL increase/a year＞1.0 mm）. There was no significant difference for the distribution and frequency of IL-1B-511 genotype and alleles between the AL increase/a year＞1.0 mm group and AL increase/a year≤1.0 mm group. The progression of periodontal disease（AL increase/a year＞1.0 mm group） was significantly high-er in the non-severe chronic periodontitis group than in the severe group（P
