Abstract: Objective To investigate the location characteristics of cystic lesions in osteonecrosis of the femoral head. Methods FromApril 2014 to September 2018,a total of 112 femoral head CT images from 65 patients diagnosed with ARCO (Association Research Circulation Osseous Committee staging system,ARCO staging system) stageⅡorⅢosteonecrosis of the femoral head admitted to our department were included.Three-dimensional structures of the femoral head including the cystic lesions and necrotic area were reconstructed.We divided each femoral head into four regions to determine the location of cystic lesions and the positional relationship of the cystic lesions with normal regions and necrotic regions. Results Of the 112 hips included in the study,45 hips had cystic lesions,and the incidence of cystic lesions in ONFH was 40.18% (45/112).The total number of cystic lesions was 76.Age,gender,BMI,and side of the lesions had no influence on the occurrence of the cystic lesions (all P>0.05);However,osteonecrosis with higher ARCO stage had higher incidence of cystic lesion (P<0.05).The most common location of cystic lesions was the anterolateral zone (40,52.63%),followed by the anteromedial zone (20,26.32%),posterolateral (8,10.53%) and posteromedial (8,10.53%) zones.Most of the cystic lesions (78.95%) were located between the normal and necrotic areas,19.74% of cystic lesions were in the necrotic area,and 1.32% were in the normal area. Conclusion The cystic lesions in the osteonecrosis of the femoral head are mainly located in the anterolateral zone of the femoral head,and are mainly distributed at the junction of the normal region and the necrotic region.