Objective To investigate the role of lysosomes in macrophage polarization. Methods In vitro model of macrophage polarization was established with RAW 264.7 cell line. M1 macrophages were obtained by coincubating of cells with lipopolysaccharide (LPS, 100 ng/ml) plus interferon-g (IFN-g, 20 ng/ml). M2 macrophages were obtained by co-incubating of cells with interleukine-4 (IL-4, 20 ng/ml). Chloroquine (25 μmol/l), a wellaccepted lysosome inhibitor, was used to treat RAW 264.7 cells. RAW 264.7 cells in sham control group did not received any treatments. Flow cytometry, ELISA, Western blot and Real-time PCR were performed to measure differential success of two cell types and lysosome markers expression including lysosome associated membrane protein 1, 2 (LAMP-1, LAMP-2) and lysosome integral membrane protein 2 (LIMP-2). Results Flow cytometry data suggested that in vitro model of macrophage polarization was successfully established. Compared with the control group, expression of lysosome makers including LAMP-1, LAPM-2 and LIMP-2 were significantly decreased in M1 macrophage subgroup while a dramatic increase of mentioned biomarkers of lysosomes was witnessed in M2 macrophages. In addition, treatment of chloroquine significantly decreased ratio of M2 macrophages over M1 macrophages. Conclusions Lysosome participates in macrophage polarization, and inhibition of lysosome facilitates differentiation of M1 polarization.