报道一例包涵体肌炎患者，女，２５岁。表现为缓慢进展的两下肢无力５年，近半年两上肢亦无力。两侧肩胛带及骨盆带肌肉轻度萎缩，肌电图示轻收缩时运动电位平均时限缩短，多相电位增多。肌活检见部分肌纤维内出现空泡，在空泡的边缘或空泡内有嗜盐基性颗粒状物质，Ⅰ型、Ⅱ型肌纤维均受累。结合文献对其病因、临床表现、肌肉病理改变、诊断和治疗进行了讨论 A case of inclusion body myositis was reported, female, 25 years old. Slowly progressing performance of the lower extremities weakness for 5 years, nearly two months, upper extremities also weakness. On both sides of the shoulder girdle and pelvic muscle mild atrophy, EMG showed mild contraction of the average duration of exercise potential shortened, multiphase potential increased. Muscle biopsy see part of the muscle fibers in the vacuole, the edge of the vacuole or vacuoles have halophilic particulate matter, type I, type II muscle fibers are involved. The etiology, clinical manifestations, changes in muscle pathology, diagnosis and treatment were discussed in combination with the literature