Objective: To evaluate the diagnostic performances of salivary gland ultrasonography(SGUS)in Sj?gren's syndrome(SS). Methods: A total of 246 patients with dry mouth and/or eyes who were treated in the outpatient department and inpatient department of Rheumatology and Immunology Department of the Ninth People's Hospital, Shanghai Jiaotong University School of Medicine from December 2019 to January 2022 were collected. All patients received SGUS examination and scored by 2019 outcome measures in rheumatology clinical trial (OMERACT)ultrasonic scoring system.Their general information, unstimulated saliva flow rate(USFR), Schirmer test and serological test results were recorded. In the study, 193 cases had lip gland biopsy. The 2016 American College of Rheumatology(ACR)/ European League Against Rheumatism(EULAR)classification criteria were adopted as the diagnostic standard of SS. χ² test was used to compare the difference of salivary gland ultrasonic scores between the two groups. The receiver operating characteristic(ROC) curve was used to evaluate the accuracy of SGUS in diagnosing SS, and the disease characteristics of SGUS positive group and negative group in the SS patients were compared. Results: A total of 175 patients were SS group according to the ACR/EULAR classification, and the remaining 71 patients were non-SS group.There was no significant difference in age [(54.2±11.8) years vs. (53.4±14.9) years, P=0.705] and female (94.4% vs.93.1%, P=1.000) between SS and non-pSS groups. A total of 109 patients were SGUS positive (≥ 2 points), of whom 104 patients met the SS diagnosis and 5 patients did not meet the SS diagnosis. The positive rate of SGUS in SS group was significantly higher than that in non-SS group (59.4% vs. 7.0%, P < 0.001). The accuracy of 2019 OMERACT ultrasonic scoring system to predict ACR/EULAR classification was good, with an area under the curve of 0.762 (95%CI 0.701-0.823). The absolute agreement between the SGUS outcome and ACR-EULAR classification was 69.1%(170/246), with a sensiti-vity of 59.4%(104/175), specificity of 93%(66/71), positive predictive value of 95.4%(104/109) and negative predictive value of 48.2% (66/137). A total of 81 patients were positive SGUS combined with anti-SSA antibody, 100% (81/81) fulfilled the ACR-EULAR criteria, 85 patients were negative SGUS and anti SSA antibody, and 60 patients(70.6%, 60/85) did not fulfil the ACR-EULAR criteria. SGUS positive group had higher antinuclear antibody(ANA) positive rate(83.1% vs. 98.1%, P < 0.001) in the patients with SS. Conclusion: The OMERACT ultrasonic scoring system has high diagnostic value in SS. The combination of SGUS and anti-SSA antibody can improve the diagnostic value.