Evidence has indicated that reducing pulmonary injury by HBO2P (hyperbaric oxygen preconditioning) in rats during simulated high‐altitude exposure (HAE). However, underlying mechanisms remains unclear. Rats were randomly divided into four groups: the non‐HBO2P+non‐HAE group, the non‐HBO2P+HAE group, the HBO2P+HAE group, and the HBO2P+HSP‐70 antibodies (Abs)+HAE group. The HBO2P groups were given 100% O2 at 2.0 absolute atmospheres for 1 hour per day for 5 consecutive days. The HAE groups were exposed to simulated HAE (9.7% O2 at 0.47 absolute atmospheres) in a hypobaric chamber for 3 days, HSP‐70 Abs were intravenously injected 24 hours before the HAE experiments. In non‐HBO2P+HAE group, the animals displayed higher scores of alveolar edema, neutrophil infiltration, and hemorrhage, and lower levels of aquaporin (AQP) 1 and AQP 5 proteins and mRNA expression in the lung compared with those of non‐HBO2P+non‐HAE controls. The increased lung injury scores and the decreased levels of both AQP1 and AQP5 proteins and mRNA expression in the lung caused by HAE was significantly reduced by HBO2P+HAE. Furthermore, HSP70 Abs, in addition to reducing lung HSP70 proteins, significantly attenuated the beneficial effects of HBO2P in HAE. Our results suggest that high‐altitude lung edema can be prevented by HSP‐70‐mediated HBO2P in rats.