Abstract： Objective To explore the expression of acid seining ion channels-3 (ASIC3) in lung tissue in rats with acute lung injury (ALI). Method Twenty four male Sprague-Dawley (SD) rats were randomly divided into four groups: LPS groups (LPS 2 h, LPS 4 h, LPS 6 h group, n=6), stimulated by LPS for 2, 4, 6 hours, respectively; normal control group, injected with saline (NS group, n=6). The ALI models were produced through venous injection of LPS, and the criteria was the characteristic pathological changes in the lung tissue. Ar-terial blood gas analysis was observed, lung wet and dry weight ratio (W/D), lung histopathology and ASIC3 ex-pression were detected. Data were expressed as mean±standard deviation. Independent Sample T test and One-way ANOVA and Kendall's tau_b were used for comparison in SPSS 13.0, and changes were considered as statistieal-ly significant if P value was less than 0.05. Results The partial pressure of oxygen (PaO2) in LPS 2 h, LPS 4 h, LPS 6 h group was (67.47±6.01), (59.17±7.18), (52.54±7.62) , respecively, and was significantly lower than that in eontrol group (98.15±1.06) (P<0.01). Compare with control group, pH was significantly lower in LPS4 h group (7.28±0.04), LPS6 h group (7.24±0.03) (P<0.01). Inflammation cells gradually increased, alveolar septum was widened, edema existed in interstitial spaces, and pulmonary structures gradually destroyed in LPS groups.The expression of ASIC3 in LPS4 h, LPS 6 h group was (205.91±10.12), (196.51± 18.60), respectively, and was significantly lower thanthat in control group (220.23±10.11) (P<0.05). The W/D in LPS 6 h group was (5.18±0.21), and was significantly higher than that in the control group (4.45± 0.18) (P<0.05). Conclusions ASIC3 is expressed in alveolar epithelial cells and bronchial epithehal cells in LPS-induced ALI rats.