Objective To explore the value of contrast-enhanced ultrasound (CEUS) computed tomography (CT)-Bosniak classification (refering to the update version of Bosniak classification [CT, 2019]) and CEUS Ruijin (RJ)-Bosniak classification in predicting benign and malignant cystic renal masses. Methods The CEUS images of 347 cystic renal masses from 316 patients who underwent CEUS in Ruijin Hospital or Wuxi Branch of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from Jun. 2015 to Jul. 2020 were retrospectively analyzed. Classification according to the CT standard of Bosniak classification (version 2019) was defined as CEUS CT-Bosniak, and that of Ruijin Hospital clinical experience was defined as CEUS RJ-Bosniak. All the patients were confirmed by biopsy or surgical pathology, enhanced CT or magnetic resonance imaging (MRI). Four grid table was used to calculate the accuracy, sensitivity and specificity of the 2 CEUS Bosniak classifications in the diagnosis of benign and malignant cystic renal masses. Results In the 347 renal cystic foci, 308 benign foci and 39 malignant foci were diagnosed based on the gold standards (the pathological results of surgery or biopsy and the final clinical diagnosis). Of the 347 lesions, there were 198 cases of category Ⅰ, 45 cases of category Ⅱ, 50 cases of category ⅡF, 26 cases of category Ⅲ, and 28 cases of category Ⅳ according to CEUS CT-Bosniak classification; 198 cases of categoryⅠ, 28 cases of category Ⅱ, 66 cases of categoryⅡF, 28 cases of category Ⅲ, and 27 cases of category Ⅳ according to CEUS RJ-Bosniak classification. Whith Bosniak categories Ⅲ and Ⅳ as diagnostic criteria of malignant foci, 290 benign and 36 malignant foci were correctly diagnosed by CEUS CT-Bosniak classification, while 292 benign lesions and 38 malignant foci were correctly diagnosed by CEUS RJ-Bosniak classification. The accuracy, sensitivity, specificity, and positive and negative predictive values between the diagnostic results of CEUS CT-Bosniak and CEUS RJ-Bosniak classification were 93.95% (326/347) and 95.10% (330/347), 92.31% (36/39) and 97.44% (38/39), 94.16% (290/308) and 94.81% (292/308), 66.67% (36/54) and 70.37% (38/54), and 98.98% (290/293) and 99.66% (292/293), respectively. The diagnostic results of the 2 standards were highly consistent with the gold standard results (Kappa values were 0.74 and 0.79, respectively). Conclusion CEUS combined with Bosniak classification has high value in differential diagnosis of benign and malignant renal cystic masses. RJ-Bosniak classification is simple and effective, which is worthy of clinical application.