In order to establish the isolation,culture and identification method of cow bone marrow-derived macrophages,three different media(RPMI-1640,DMEM,DMEM/F12)were added with 20%fetal bovine serum(FBS),2.4%chlorine-streptomycin,1.2%glutamine(Gln),and M-CSF(20 ng/mL),respectively,to induce the monocytes extracted from the bone marrow of dairy cows to become macrophages.The induced M0 macrophages were polarized into M1-type macrophages by adding lipopolysaccharide(LPS).The morphology of macrophages was observed by optical mi-croscope at day 1,4 and 7,and the differences of differentiated macrophages between the three media were compared.The effects of prostaglandin D2(PGD2)-DP2 receptor pathway on the secre-tion of cytokines(IL-6,TNF-α)induced by Escherichia coli and phagocytosis of macrophages were also investigated.The results showed that the morphological changes of cells cultured in the medium of RPMI-1640 were the most obvious and the number was large.A large number of char-acteristic markers of mononuclear macrophages were detected(M0 markers:CD1 1b,CD14;M1 markers:CD11b,CD80)expression,M0 and M1 macrophage purity were 79.9%and 93.5%,re-spectively.COX-2 and H-PGDS gene expressions were significantly increased in E.coli group com-pared with the blank control group.The secretion of PGD2also increased significantly(P<0.000 1).DP2 receptor inhibitors(CAY10471,CAY10595)could significantly inhibit the secretion of E.coli in-duced pro-inflammatory cytokines(IL-6,TNF-α)and significantly enhance the killing effect of macrophages on E.coli.The above results showed that the induced cells had the characteristic mor-phology and immunophenotype of macrophages.E.coli can induce the production of PGD2 in mac-rophages,and the PGD2-DP2 pathway regulates the secretion of cytokines in E.coli infected macro-phages.