Objective To explore the value of ultrasound/CT fusion imaging in the differential diagnosis of renal tumors. Methods The ultrasonic and CT imaging data of 79 patients with pathologically confirmed renal tumors diagnosed between June 2014 and June 2016 were analyzed retrospectively. The ultrasound/CT fusion imaging analysis was performed. Results There were 57 cases of renal malignant tumors, and most of them showed low echo or equal echo on ultrasound images. CDFI showed that there were color blood flow signals in the tumors in 53 cases and fine blood flow around the tumors in 4 cases. CT scan mainly showed low density, and the enhanced scan mainly showed high or equal enhancement. There were 22 cases of benign tumors, and most of them showed high echo on ultrasound images. CDFI showed no blood flow signals in most of them, and there were only 4 cases with fine blood flow around the tumors. CT scan mainly showed low density, and most of them showed low or equal enhancement. There were significant differences among ultrasound/CT fusion, CT and ultrasound in accuracy rates (96.20%, 84.81%, 70.89%), sensitivities (96.49%, 85.96%, 73.68%) and specificities (95.45%, 81.82%, 63.64%) in the diagnosis of renal tumors (P<0.05). Conclusion Ultrasound/CT fusion imaging integrates the advantages of ultrasound and CT scan. It can improve the accuracy of qualitative diagnosis of renal tumors, and it is helpful to guide clinical treatment.