The effect of Houttuynia cordata polysaccharide (HCP) on LPS induced chronic inflammatory lung injury was investigated in the present work. The chronic inflammatory model was established via the intravenous injection of LPS, and the number of WBC, monocyte and the content of serum hypersensitive C-reactive protein (hs-CRP) were measured in this work. Furthermore, the pathological changes of lung tissue were observed. The contents of antioxidant enzyme, malondialdehyde (MDA), nitric oxide (NO), nitric oxide synthase and the level of cytokines in lung tissue were determined. The results showed that, the content of WBC, monocyte and serum hs-CRP in high dose treatment of HCP group were significantly reduced by 17.89%, 38.37% and 35.61% respectively, when compared to LPS group. Moreover, pathological observation showed that HCP treatment group could alleviate significantly the pathological state of pulmonary edema. Meanwhile, the activity of antioxidant enzyme in lung tissue of HCP treatment group was significantly increased. Strikingly, the content of MDA, NO, iNOS, tNOS and the cytokine levels of IL-6, IL-1β, TNF-α in high dose treatment of HCP group were remarkably reduced by 28.79%, 22.88%, 37.06%, 27.49%, 34.19%, 38.84% and 52.27%, respectively. In conclusion, the protective effects of HCP against chronic inflammatory lung injury in rats was linked to its activities on the reduction of inflammatory cell secretion, the alleviation of pulmonary edema and other pathological states, the inhibition of oxidative stress, and the reduction of the release of inflammatory factors.