Abstract： A 20-year-old woman presented with progressive facial deformity and exophthalmos for 20 years and with decreased vision for about 1 year in her left eye.Exophthalmometry measurements was 12 mm＞90 mm＜16 mm and her best corrected visual acuity was 0.8 in the left eye,with mild impairment of peripheral visual field and limited eye movement in the left eye as well.According to clinical manifestations and orbital CT images,the patient was diagnosed with polyosseous fibrous dysplasia of bone and subsequently underwent endoscope-navigation-assisted orbital margin trimming,orbital decompression,jaw trimming and zygomatic arch coarctation for her left periorbital lesion.Postoperative pathology and molecular tests further confirmed the diagnosis of fibrous dysplasia of bone.The patient's lesions have remained stable without any symptom recurrence for four years after surgery.The difficulty in the treatment of fibrous dysplasia of bone lies in the selection of surgical time and surgical procedure.The patients'age,the number and location of lesions,the growth rate of lesion bones,the severity and cause of functional impairment,and patients'psychological status should be considered comprehensively before making treatment decisions.