Abstract: To discuss the inhibiting effect of onion quercetin on inflammatory response, this paper took mice's enterocoelia macrophage as sample and used MTT to investigate the impact of onion quercetin single drug group, combination drug of onion quercetin and LPS group on macrophage's phagocytosis, used ELISA to investigate the impact of onion quercetin single drug group, combination drug of onion quercetin and LPS group on cytokines and inflammatory mediator secretion from mice 's enterocoelia macrophage.The result showed that onion quercetin can improve phagocytosis of macrophage; onion quercetin single drug and combination drug of onion quercetin and LPS can stimulate macrophage of IL-1β and COX-2 which induces secretion of macrophage.In summary, onion quercetin may inhibit inflammation via improving macrophage's phagocytosis and affecting secretion of cytokines and inflammatory mediator.