Abstract: Objective：To investigate serum miR-146a levels in the patients with rheumatoid arthritis(RA) detected by SYBR GreenⅠ real-time fluorescence quantitative PCR(FQ-PCR), and its significance in the diagnosis of RA. Methods：The levels of serum miR-146a were detected by FQ-PCR with U6 as internal reference in 48 patients with RA, including 30 active RA and 18 inactive RA, 22 patients with osteoarthritis(OA) and 25 healthy controls, and the obtained ROC curve was analyzed. Meanwhile, erythrocyte sedimentation rate(ESR) for all subjects was determined. Results：he relative expression levels of serum miR-146a in the patients with active RA(2.42±0.75) were significantly higher than those in the patients with inactive RA(1.66±0.29), the OA patients(1.12±0.43) and healthy controls(1.01±0.34)(P0.05). The area under the curve(AUC^ROC) for miR-146a in the diagnosis of active RA was 0.914(95%CI: 0.872 0.926).When the cut off value was set at 1.96, the sensitivity was 95%, the specificity was 87.5%, and the accuracy was 91.9%. The ESR values in active RA patients, inactive RA patients, OA patients and healthy controls were(37.5±5.2) mm/h,(14.4±4.7) mm/h,(11.6±5.1) mm/h and(9.6±3.9) mm/h, respectively, and there was significant difference between them(F=177.01, P<0.01). Conclusion：The established FQ-PCR can be used to detect the levels of serum miR-146a in RA patients. miR-146a can be used for diagnosing active RA.