To study injurious effects on rabbit lung from rapid decompression, slow decompression and the rapid decompression were used in two respective groups consisting of 30 rabbits. Slow decompression did not bring about obvious lung injury, but the lung injury in different severity occurred after rapid decompression. The greater the decompression peak value was, the more severe lung injuries was. These results indicated that rapid decompression could inflict lung injury, and the main cause of lung injury might be the temporary high pressure in lungs induced by rapid decompression, leading to over expansion of the alveoli and strong impact of the lung on the chest wall