Osteopoikilosis is an extremely rare fragile bone sclerosis disease, which is clinically asymptomatic and usually found by accident. One case with right ankle fractures is found. X-ray examination showed uneven distributions of dense shadow in different sizes. Diagnosis of osteopoikilosis was confirmed by further examination. Epiphyseal and metaphyseal regions near the joint were mainly involved rather than soft tissues. It had no signs of bone fragility, nor blood chemical composition change. Treatment is not needed commonly, with good prognosis. Osteopoikilosis should be differentiated with osteogenic metastasis.