Objective To evaluate the differences among five representative and useful Doppler parameters in the diagnosis of the three common types of renal artery stenosis (RAS). Methods Five Doppler parameters including renal peak systolic velocity (RPSV), renal-aortic ratio (RAR), renal-interlobar ratio (RIR),acceleration time (AT),and resistant index (RI) were measured in 221 patients before renal arteriography. Differences between the groups of patients with various clinical causes of RAS were analyzed by Chi-Squared test. One-way ANOVA or t test were used to compare the means between different groups.The optimal cutoff value was determined with the maximum sum of sensitivity and specificity. Results Of the 442 renal arteries (main and accessory renal arteries) demonstrated at arteriography,214 were normal or stenosed less than 50 %, 204 stenoses 50% - 99 %, and 24 occlusions. RIR, RAR and RI were significantly different between the atherosclerotic and non-atherosclerotic RAS groups (P ＜0.05), while RPSV and AT were not. The optimal cutoff values of RAR,RIR and RI for detecting RAS between the atherosclerotic and non-atherosclerotic groups were much different (2.5 versus 1.9, 5. 1 versus 6.5, 0.57 versus 0.50,respectively) ,but those of RPSV and AT were similar or the same (170 cm/s versus 200 cm/s,51 ms versus 51 ms,respectively). Conclusions In the case of RAS (diameter reduction≥50%),it is advised to establish separate cutoff values of RAR, RIR and RI according to atherosclerotic and non-atherosclerotic RAS, but the same cutoff value of RPSV and AT can be applied. RIR is a good Doppler parameter in the diagnosis of RAS,especially atherosclerotic and fibromuscular dysplasia RAS.