Abstract： Objective To detect the expression of Toll-like receptor 9 (TLR9) in pancreatic cancer,and to explore its clinical significance. Methods The real-time PCR, Western blotting and immunohistochemistry were used to examine the expression of TLR9 in 30 samples of pancreatic cancer and the adjacent tissues, and 10 samples of normal pancreatic tissues. The relationships of TLR9 with clinicopathological parameters were analyzed. Results Compared with normal pancreatic tissues, the amplification value of TLR9 mRNA expression was 2.32 fold (1.41 ～ 3.22 ) in human pancreatic cancer, was 1.23 fold (1.18 ～ 1.28) in paracancerous tissues, respectively, and the difference was statistically significant (P ＜ 0.05 ). The percentage of positive cells expressing TLR9 protein in human pancreatic cancer tissues,paracancerous tissues and normal tissues were 73.3% (22/30), 33.3% (10/30) and 20.0% (2/10), and the relative expressions of TLR9 protein were 0.780 ±0. 026,0. 400 ±0.018,0. 173 ±0.043 ,respectively, and the difference was statistically significant( P ＜ 0.05 ). The highly expressed TLR9 was positively correlated with the degree of tumor differentiation, TNM stage and lymph node metastasis. Conclusions TLR9 was highly expressed in pancreatic cancer tissues. TLR9 expression plays a role in the canceration of pancreatic tissues.