〔Abstract〕 Objective To explore the role and molecular mechanism of parthenolide(PTL) in regulating tumor-associated macrophage(TAM) polarization to inhibit the malignant progression of gallbladder cancer cells. Methods M0 macrophages were co-cultured with human gallbladder cancer cell line GBC-SD and treated with PTL, and the cells were divided into control group, TAM group, TAM+PTL group. Flow cytometry was used to determine the levels of CD86 and CD206 in macrophages. RT-qPCR and Western blot were used to determine the expressions of CD163, interleukin-10(IL-10) and arginase-1(Arg-1). ELISA and Western blot were used to determine the secretion of CC chemokine ligand 2(CCL2) in the supernatant of GBC-SD cells and the expression of CCL2 in the cells. GBC-SD cells were transfected with a CCL2 overexpression vector and divided into TAM, TAM+PTL, TAM+PTL+OE-NC, TAM+PTL+OE-CCL2 groups. Flow cytometry was used to assess CD86 and CD206 levels in macrophages, RT-qPCR and Western blot were used to assess CD163, IL-10 and Arg-1 expression. CCK-8 assay, plate-based colony formation assay and Transwell chamber assay were used to assess GBC-SD cell proliferation, migration and invasion, respectively. Results Compared with the TAM group, the TAM+PTL group showed increased CD86 expression and decreased CD206 expression in macrophages, the mRNA and protein expressions of CD163, IL-10 and Arg-1 were downregulated, the CCL2 content and protein expression in GBC-SD cells decreased, cell proliferation activity, colony formation, migration and invasion were all reduced(P