Abstract: Objective To under stand the epidemiologic characters of ankylosing spondylitis(AS) and to analyze the disease history and the distribution of AS-related disease index.Methods Totally 445 AS patients from Deparmtent of Rheumatism in First Affiliated Hospital of Anhui Medical University were investigated with a self-designed questionnaire.Results The average onsetage of the patients was 23.6±8.3 years.The male to female ratio of the patients was 5.54: 1.There was a significant difference in the onsetage of AS between male and female patients(t=3.8, P<0.01).The median of disease duration (MP25, P75) was 4.42(2.04, 8.04) years with a significant difference between male and female (Z=2.50, P<0.05).There were 50.1% of the patients reported low back pain or discom fort as the first symptom.Mean total index of backache was 2.24±2.48 for jurenile-onset AS and 3.04±2.86 for adult-onset AS (t=2.06, P<0.05).Conclusion AS mainly invades young males, and the average onsetage of menis younger than that of women.The young men with peripheral joint symptoms or lower back discom fort should be early screened, particularly for those with family history of seronegative spondy loarthropathy.