Abstract： Objective To investigate the effect of interleukin 6 (IL-6) on the growth and proliferation of human pancreatic cancer cell line Capan-2 and the signal transduction pathway. Methods MTr method was used to detect the effect of IL-6 of different concentrations on the growth and proliferation of Capan - 2 cells; cell apoptosis was detected by flow cytometry; the intracellular localization of phosphorylated STAT3 (P-STAT3) was determined by immunocytochemistry and western blot were used to detect P-STAT3, bcl-xl and Cyclin D1 in Capan-2 cells stimulated by IL-6. Results IL-6 (100 ng/ml) could remarkably promote the growth of Capan-2 cells from 1 to 4. 965 ± 0. 18 (P < 0. 05) ; the percentage of apoptosis decreased significantly from (3.21 ±0.23)% to (1.98 ±0.67)% (P <0.05) ; the expressions of P-STAT3, bcl-xl, Cyelin D1 increased significantly (P < 0.05), and the expressions of bcl-xl was positively correlated with that of P-STAT3 (r =0.985, P =0.015) ; the expressions of Cyclin DI was also positively correlated with that of P-STAT3(r=0.914,P=0.036),Conclusions IL-6 activate JAK/STAT signal transduction pathway,which played an important role in the growth and proliferation of Capan-2 cells in the presence of IL-6.