Abstract: Objective To determine the correlation between quantitative results of contrast-enhanced ultrasound and clinical and laboratory index for synovium of patients with rheumatoid arthritis (RA). Methods Thirty-five RA patients participated in this study, with ten normal adults serving as controls. They were given a score of DAS28 and underwent laboratory tests, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Contrast-enhanced ultrasound examinations were performed to detect thickness of synovium (2D and Power Dopple). Results Peak intensity (PI) and area under the curve (AUC） were positively correlated with ESR, CRP and DAS28 score, respectively (P<0.01). The rest of ultrasound parameters had no significant correlations with ESR, CRP and DAS28 score (P>0.05). Synovium thickness identified by contrast-enhanced ultrasound had significant correlations with ESR, CRP and DAS28 score (P<0.01). Conclusion Synovium thickness determined by contrast-enhanced ultrasound, PI and AUC can serve as an index estimating inflammatory activity of RA, and provide evidence for clinical diagnosis and treatment.