Objective To investigate the value of CT and determination of bone mineral density in the diagnosis of aseptic necrosis of femoral head. Methods Forty-six cases with aseptic necrosis of the femoral head treated in our hospital between March 2015 and May 2016 were selected as the study subjects. All cases underwent CT examination and bone mineral density detection before operation. The CT findings included not obvious change or a bit change of density, star sign in stage I , cystic bright and patchy bone sclerosis and cystic bone resorption in stage II, obvious deformation or disappearance of trabeculae in femoral head, narrow and thin broad band under the articular surface of upper and anterior femoral head, namely, the crescent sign in stage III, femoral head deformation and changes of spaces, around or irregular sclerosis in stage IV. The bone mineral density and bone mineral content were recorded. The sensitivity, specificity and accuracy of CT and determination of bone mineral density and single CT scan in the diagnosis of aseptic necrosis of femoral head were compared and evaluated. Results The results of CT examination showed that there were 6 cases in stage I, 19 cases in stage II, 15 cases in stage III anf 6 cases in stage IV. The results of bone mineral density determination showed that bone mineral density and bone mineral content in the region of interest of femoral neck and hip in male patients were higher than those in female patients (P<0.05). The Kappa value of consistency test was 0.743 (P<0.05). The diagnostic sensitivity and accuracy of CT combined with determination of bone mineral density (80.00%, 78.26%) were significantly higher than those of simple CT examination (P<0.05) in the diagnosis of aseptic necrosis of femoral head. The area under ROC of CT and bone mineral density detection in the diagnosis of femoral aseptic necrosis (0.947) was significantly larger than that of simple CT examination (P<0.05). Conclusion Conbined CT and determination of bone mineral density is of high value in the diagnosis of aseptic necrosis of the femoral head.