Abstract: Objective: To investigate the mRNA transcription and protein expression of MMP-3.Possible roles of MMP-3 in primary sjogren′s syndrome（pSS） were analyzed. Methods: For this study,24 patients with pSS were selected and diagnosed by the American-European Consensus Group standards.The control group was composed of 14 subjects.Total RNA from labial glands was extracted.The target genes and β-actin acted as templates to perform reverse transcript polymerase chain reaction（RT-PCR）.Then mRNA expression of target genes was semi-quantitated by the OD ratio of the target genes to β-actin bands on gel under densitometry.Immunohistochemical analysis was made to determine the expression of proteins of targets genes in labial glands of pSS patients and control group. Results: In contrast to control group,the mRNA transcription and protein level of target genes in labial glands of pSS patients were significantly increased statistically（P＜0.05）,and MMP-3 protein was mainly expressed in intracytoplasm of gland duct. Conclusion: The increase of MMP-3 in pSS patients provides a rationale for understanding the organization observed in the basal lamina and apical surface of acini in these patients.