Objective To study the clinical characteristics of the adult onset Still's disease(AODS),its concomitant symptoms,and misdiagnosis.Methods To analyze retrospectively 12 adults who were diagnosed bosh by clinical treatment and laboratory examination as AODS patients.Results 12 cases suffered from fever,9 cases from dermatitis and arthralgia,3 cases from muscle pains,3 cases from enlarged liver,4 cases from enlarged spleen,3 cases from enlarged liver and spleen,and 3 cases from abdomen pain.Conclusion AODS does not have special symptoms in its early stage.Its complexity often results in a missdiagnosis.