Objective: To systematically evaluate the value of circulating miR-21 in diagnosis of pancreatic cancer through Meta-analysis. Methods: The studying data concerning using circulating miR-21 in diagnosis of pancreatic cancer published before May 2017 were collected through searching several national and international databases. After screening for inclusion criteria, data extraction and quality assessment, Meta-analysis was performed by using MetaDisc 1.4 and Stata 14.0 software. Results: A total of 8 studies were included with 261 pancreatic cancer patients and 242 control subjects. The results of Meta-analysis showed that the pooled sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of circulating miR-21 for diagnosis of pancreatic cancer was 0.76 (95% CI=0.71–0.81), 0.76 (95% CI=0.70–0.81), 3.17 (95% CI=2.24–4.47) and 0.26 (95% CI=0.15–0.45), respectively. The diagnostic odds ratio value was 13.17 (95% CI=6.78–25.58), and the area under the summary receiver operator characteristic curve (AUC) was 0.8518. Subgroup analysis showed that the serum and plasma subgroups had a same AUC value of 0.8513, and the diagnostic accuracy of the healthy population control subgroup was better than that of the health population plus benign pancreatic disease patients control subgroup (AUC: 0.876 vs. 0.72, P<0.05). The Deek’s funnel plot for the diagnostic test showed that there was no publication bias, and the sensitivity analysis showed that the results of this analysis were not strongly dependent on any single study and that the conclusions were stable. Conclusion: Circulating miR-21 has certain value in diagnosis of pancreatic cancer.