Objective: To explore the application value of superb microvascular imaging (SMI) in detecting the synovial blood vessels of knee joint in patients with rheumatoid arthritis (RA), by comparing with contrast-enhanced ultrasound (CEUS). Methods: SMI and CEUS were respectively used to detect and record the blood flow signals of synovium of knee joint of 52 RA patients undergoing total knee arthroplasty (TKA). The consistency of grading of synovial vessels by SMI and CEUS, as well as the correlation between SMI grading and pathological grading were analyzed. Results: There were 104 knee joints in 52 patients, 63 of them underwent total knee arthroplasty. SMI and CEUS all displayed 92.31% (96/104) of the synovial blood flow signals of the knee joint of RA patients, and the consistency between SMI and CEUS was high (Kappa=0.724). Spearman correlation analysis showed that SMI grading was positively correlated with pathological grading (r=0.744, P<0.05). Conclusions: Displaying the synovial blood flow signals of the knee joint of RA patients by SMI was consistent with CEUS; Moreover, SMI can provide some reference value for judging the activity of RA.