Objective To explore the effect of hepatocyte growth factor (HGF) on the proliferation, apoptosis and function of hyperoxia exposed Type II alveolar epithelial cells (AEC II) isolated from premature rat lungs, and to explore the mechanism of the protective effect of HGF on hyperoxia-induced lung injury. Methods Type II alveolar epithelial cells from fetal rat lungs were cultured. After being purified , AEC II was randomly dividid to 4 groups: air group (Air), hyperoxia group (HO), air plus hepatocyte growth factor group (Air + HGF), hyperoxia plus hepatocyte growth factor group (HO + HGF). The mRNA levels of surfactant associated protein, SPs (including SPA, SPB, SPC) were measured by RT-PCR. The proliferation and apoptosis of AEC II were analyzed with flow cytometric assay and Western blot. Results (1) Compared with Air group, the apoptosis rate increased significantly in the HO group, while G2/M phase percentage and the protein expression levels of proliferating cell nuclear antigen (PCNA) decreased significantly (P < 0. 01); the S phase percentage and the protein expression levels of PCNA increased significantly in the Air + HGF group. (2) In the HO + HGF group, the apoptosis rate was not significantly different, G0/G1 phase percentage decreased significantly, S phase, G2/M phase percentage and the protein expression levels of PCNA increased significantly compared with the HO group. (3) SPs mRNA levels significantly decreased in the HO group compared with those in the Air group. After HGF was added, SPs mRNA levels increased in the HO + HGF group and the Air + HGF group compared with the HO group. Conclusion Hyperoxia can inhibit the proliferation, increase the apoptosis rate and decrease SPs mRNAs levels of AEC II in vitro in premature rats, while HGF can partly inhibit the changes of SPs mRNAs levels and cell proliferation of AEC II resulted from hyperoxia, and HGF may play a protective role in hyperoxia-induced lung injury.