Objective  To explore the effect of imiquimod (IMQ) on the proliferation of  glioma U87 cell line U87.   Methods  U87 cells were divided into control group, 1 mmol/L I mmol/L MQ group, 5mmol/L IMQ group, 1 mmol/L IMQ+STAT3 inhibitor（STAT3-IN） group and 5 mmol/L IMQ+STAT3-IN group. To detect the number of 5-ethynyl-2’-deoxyuridine(EdU)-labeled cells or proliferation absorbance(A) values in each group by EdU and MTT assays. Interleukin(IL)-6 mRNA, tumor necrosis factor(TNF)-α mRNA and protein content in U87 cells of each group were detected by Real-time PCR or ELISA. Western blotting was used to detect the protein expression of STAT3, phosphorylated STAT3 (p-STAT3), nuclear factor(NF)-κB and phosphorylated NF-κB (p-NF-κB) in U87 cells of each group.  Results  Compared with the control group, the number of EdU-labeled cells and absorbance values of U87 cells were successively decreased in 1mmol/L IMQ group and 5mmol/L IMQ group, showing a dose-dependent manner (P＜0.01, n=10). However, the number of EdU-labeled cells and the A values in IMQ+STAT3-IN group and 5 mmol/L IMQ+STAT3-IN group were significantly reduced. Compared with the control group, the protein expression of STAT3, p-STAT3, NF-κB, p-NF-κB, IL-6 and TNF-α were continuing low level in U87 cells of 1mmol/L IMQ group and 5mmol/L IMQ group (P＜0.01, n=10). As well as in 1 mmol/L IMQ+STAT3-INgroup and 5 mmol/L IMQ+STAT3-IN group, the proteins of above were low expressed (P＜0.01, n=10).   Conclusion Imiquimod decreased the contents of IL-6 and TNF-α by down-regulating STAT3/NF-κB pathway, and thus inhibited the proliferation of U87 cells.