Background and Aims Pancreatic cancer is a common tumor of the digestive system and a frequent cause of cancer-related death. Long non-coding RNAs (lncRNAs) have been demonstrated as regulators and specific biomarkers for multiple cancers. Recent evidence has indicated that the novel lncRNA SOX21-AS1 plays an important role in the initiation and progression of a variety of malignant tumors. However, its function in pancreatic cancer remains unclear. Therefore, this study was conducted to investigate the expression of SOX21-AS1 in pancreatic cancer and its function.Methods The expressions of SOX21-AS1 in 20 pairs of specimens of pancreatic cancer and adjacent normal tissue as well as in a range of pancreatic cancer cell lines (PANC-1, CAPAN2, CFPAC-1, BXPC3, and SW1990) and human pancreatic duct epithelial cell line (HPDE) were detected by qRT-PCR method. The relationship between SOX21-AS1 expression and the prognosis of pancreatic cancer patients were analyzed through GEPIA database. The changes in cell viability and proliferative capacity in pancreatic cancer cells after SOX21-AS1 silencing were determined by MTT assay and colony-forming assay. The targeted microRNAs (miRNAs) of SOX21-AS1 and its downstream targeted mRNAs were predicted using DIANA database, and then the interactions among them were validated by a series of function experiments, dual luciferase reporter assays, rescue experiments and correlation analyses.Results The expressions of SOX21-AS1 were upregulated in both pancreatic cancer tissue and cell lines, and the patients with its high expression had a poor prognosis (all P<0.05). In pancreatic cancer cells after SOX21-AS1 silencing, the cell viability and proliferative ability were significantly decreased (both P<0.05). Bioinformatics analysis indicated that there was a target binding sequence in miR-31-5p for both SOX21-AS1 and MMP-16 mRNA, and the interactions among them were confirmed by function experiments, dual luciferase reporter assays and rescue experiments. In addition, the results of correlation analysis showed that there was a negative correlation either between SOX21-AS1 expression and miR-31-5p expression (r²=0.257 1, P<0.05), or between miR-31-5p expression MMP-16 mRNA expression (r2=0.311 3, P=0.010 6).Conclusion The increased expression of SOX21-AS1 is associated with the enhanced viability and proliferation of pancreatic cancer cells, as well as the poor prognosis of pancreatic cancer patients. In terms of mechanism, SOX21-AS1 may competitively bind to miR-31-5p as a competing endogenous RNA (ceRNA) to regulate the expression of MMP-16 mRNA, thereby promoting the progression of pancreatic cancer. SOX21-AS1 may probably be a potential biomarker and therapeutic target for pancreatic cancer.