AIM: To investigated the mechanism of action of Yiqi tongfu xiere prescription (YTX) in treating mice with lipopolysaccharide (LPS)-induced acute lung injury (ALI). METHODS: According to the random number table, 24 C57BL/6 mice were divided into 4 groups: control group (Control), model group (LPS), low dose group (YTX-L) and high dose group (YTX-H). Except for the control group, the mice models of acute lung injury were established by intratracheal instillation of LPS solution (5 mg/kg). The low and high dose treatment groups were given intragastric administration continuously for 14 days. After 24 hours, the lung tissue, bronchoalveolar lavage fluid (BALF) and serum of the four groups were taken for follow-up detection. The degree of pulmonary edema was evaluated by wet weight coefficient (wet to dry ratio, W/D) of lung tissue. The degree of alveolar inflammation and pulmonary fibrosis were evaluated by HE and Masson staining, and the contents of BALF and serum inflammatory cytokines IL-1 β and IL-6 were detected by ELISA. The protein expressions of α-SMA, FN, Col-I and Col-III were measured by Western blot. Determination of α-SMA, FN, Col-I, MAPK, NF-κB mRNA expression by RT-PCR method. RESULTS: Compared with LPS group, the contents of BALF, IL-1 β and IL-6 in serum, Wmax D ratio, lung pathology, serum α-SMA, FN, Col-I, Col-III protein expression and α-SMA, FN, Col-I, MAPK, NF-κB mRNA expression in treatment group were significantly lower than those in control group. CONCLUSION: YTX can significantly reduce the levels of pulmonary fibrosis markers such as α-SMA, FN, Col-I and Col-III by inhibiting the activation of MAPK/NF-κB signal pathway, and improve alveolar inflammation and pulmonary fibrosis in mice with lung injury, suggesting that YTX can treat acute lung injury and provide a theoretical basis for the clinical use of YTX.