Abstract: Adult-onset Still's disease (AOSD) is a rare autoinflammatory disorder characterized by nonspecific clinical manifestations and the absence of definitive laboratory markers. This article presents a case of a 34-yearold female diagnosed with AOSD after delivery. The patient exhibited a rash and recurrent high fever during the late stages of pregnancy, and delivered a premature infant weighing 1, 760 g and underwent a cesarean section on October 7, 2024. After a consultation by a multidisciplinary team (MDT), the patient was diagnosed with AOSD. The patient was discharged from the obstetrics department on October 15, 2024, and transferred to the rheumatology and immunology department for treatment with methylprednisolone 40 mg administered once a day. The patient was discharged from the hospital on October 21, 2024, as her condition improved after treatment and she had no recurrence of fever after October 17, 2024. At the 42-day postpartum follow-up, the patient's inflammatory markers and serum ferritin levels were roughly restored to normal, and her general condition was good. Through a review of this case and relevant literature, this article summarizes the clinical features and laboratory indicators of AOSD, discusses its diagnosis, differential diagnosis, and treatment, and provides clinical insights to assist clinicians in achieving accurate diagnosis and avoiding misdiagnosis.