Results: there were 30 cases diagnosed as JAS by Amor's criteria at the children's hospital No 2 from 1/2000 to 6/2007, our data showed that: male to female ratio 3.28/1, age at onset 10.1 ± 5 years old, age at diagnosed 11.7 ± 4.9 years old, median duration of disease at presentation 12 months, 83.3% of the cases first manifested by peripheral arthritis, especially in large joints of lower limbs, most of the patients suffer from enthesitis.