Chondroma is harmful if not removed, which can cause pain, pathological fracture and deformity. 1. Pain and activity limitation: it is due to the increasing size of chondrosarcoma that forms compression on tendons and nerves, which leads to the symptoms of local pain and activity limitation. 2. Pathological fracture: if the chondroma is not removed for a long time, with the increasing of tumor, it can destroy the normal bone structure, which can make the bone fracture under slight external force. Meanwhile, it is also accompanied by local pain, swelling and dysfunction and other symptoms. 3. Deformity: due to not removing chondrosarcoma in time, the enlargement of tumor will cause knee valgus, unequal length of both lower limbs and deformation of fingers or toes, which will lead to deformity. To sum up, chondroma will cause more harm if not removed in time, and it is suggested that patients should go to regular hospitals in time and have relevant medical examination and treatment under doctors’ guidance.