Objective To explore the etiology,clinical features,and imaging features of multiple osteochondroma.Methods A total of 21 patients of multiple osteochondroma with completely clinical and imaging data were brought into this study.All these patients accepted X ray DR examination, and 15 cases of them accepted CT scanning and 4 cases of them accepted MRI examination.The clinical and imaging data were analyzed retrospectively combined with the relative literature.Results All the 21 patients with multiple osteochondroma had family history,and it's likely to be found in the metaphysis of limb long bone.Patients with multiple osteochondroma usually had bony lump with cartilage cap in long bones' metaphysis.It often occured in double sides but not symmetry,and it was more likely to be found in the lower limbs.Bone around the knee-joint was the most common position of lesion,and the growth direction was usually deviating from the joints.Conclusion Multiple osteochondroma has the characteristics of internalization bone cartilage defects and osseous vegetations formation,and it's usually combined with bone bending,shortening deformity and adjacent joint activities obstacles.It can be diagnosed according to the typical clinical features,X-ray and CT imaging features.