【】 Objective To compare the diagnostic efficacy of conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS) in renal cystic lesions. Methods From June 2014 to November 2015, twenty-nine patients with twenty-nine renal cystic lesions underwent CEUS and US in our department．Images were analyzed by two ultrasonographers engaged in CEUS more than 10-year and 2-year respectively. All masses were graded benign or malignant according to features of the US and CEUS images, and the terminal diagnosis of these lesions were confirmed by pathology. The sensitivity, specificity, accuracy, positive predictive value, negative predictive value and the diagnostic consistency were evaluated, and the diagnostic value of US and CEUS were compared. Results The sensitivity, specificity ,accuracy ,positive predictive value, negative predictive value and The area under the ROC curves of US and CEUS were 66.7% vs 94.4%,72.7 %vs 81.8%,80.0%vs89.5%,57,1%vs90.0%,68.9% vs 89.7%, 0.697vs 0.874. There were significant differences in diagnosing renal malignant cystic lesions between the 2 groups(p=0.04)．Conclusions CEUS is helpful for improving the diagnostic efficacy of renal malignant cystic mass．