Objective:Research value of articular ultrasound in the differential diagnosis of serological negative rheumatoid arthritis and osteoarthritis. Methods:145 cases of OA and SNRA with the main complaint of knee, elbow, wrist or proximal interphalangeal joint pain were included and examined by routine doppler ultrasonography, focusing on bone erosion, synovial thickening, and synovial blood flow signal evaluation. Diagnosis was made according to ACR/EULAR criteria after 6 months follow-up. The main differences of ultrasonic features between SNRA and OA groups were compared. Results:A total of 145 patients and 425 joints were examined in this study. 75 patients with 194 joints were in the OA group and 70 patients with in the SNRA group. In aspect of SNRA diagnosis,2-3 grade degree bone erosion has the specificity of 93.33 and the sensitivity of 41.82%. In 0-1 degree bone erosion cases, the degree of synovial thickening and the difference of synovial blood flow signal were significantly different between SNRA and OA groups (p<0.01). Conclusion:Ultrasound play important role in identifying SNRA and OA in bone erosion and synovitis evaluation.