Abstract: Objective To study the application of quantitative ^99mTcO₄^-dynamic salivary gland images in diagnosis of primary Sjogren syndrome (pSS). Methods Forty-four pSS patients served as a pSS group and 28 healthy subjects served as a control group in this study. Their ^99mTcO₄^-dynamic salivary gland images were observed. Time-activity curve (TAC) of gland and its function parameters, including uptake ratio (UR), relative uptake ratio (S/T), gland secretion rate (SR) and mean secretion velocity (SV) after acid stimulation, were collected from the drawing region of interest (ROI). Difference in each function parameter was analyzed between pSS group and control group. The accuracy of quantitative ^99mTcO₄^-dynamic salivary gland images was assessed according to the ROC curve. Results The gland UR and S/T were significantly lower, the gland SR after acid stimulation was significantly lower, the gland SV after acid stimulation was significantly slower in pSS group than in control group (P﹤0.01). ROC curve showed that the sensitivity of gland SV and the specificity of gland UR were the highest in diagnosis of pSS among the parameters. Conclusion Quantitative ^99mTcO₄^-dynamic salivary gland images can be used in diagnosis of pSS with a high sensitivity and specificity, thus playing an important role in assessment of the uptake and secretion function of salivary gland.