Abstract: In order to study the effects of different hypobaric conditions (0.10, 0.06, 0.04, 0.02 MPa) on storage quality and physiological and biochemical indices of Pleurotus eryngii, the experiment was carried out with Pleurotus eryngii as materials, which were vacuum-packed with 0.07 mm low density polyethylene bags, and stored in 4℃. The results showed that, compared with normal pressure (0.10 MPa), hypobaric storage under 0.06 and 0.04 MPa not only reduced the respiration rate of Pleurotus eryngii at different degrees and maintained the activities of superoxide dismutase (SOD) and catalase (CAT), but also inhibited the increase of malondialdehyde (MDA), which delayed aging process, and inhibited the activity of polyphenol oxidase (PPO), which delayed browning degree. So the hardness, springiness, cohesiveness, chewiness and the color of Pleurotus eryngii were better maintained under 0.06 and 0.04 MPa, among which the effect of hypobaric storage under 0.04 MPa was better. It also showed that, from 0.10 to 0.04 MPa, the lower the pressure, the better the effect of the hypobaric storage. But when Pleurotus eryngii was stored under 0.02 MPa, the changes of storage quality did not obey the law. Under this storage pressure, the change law of the respiration rate, the activity of CAT, the hardness of pileus, the springiness and chewiness of pileus and stipe all showed abnormal conditions. At the same time, abnormal conditions were found in the variations of the activity of PPO, the color and the MDA content of Pleurotus eryngii which was stored under 0.02 MPa. The cause of these abnormal conditions may be when the storage pressure was 0.02 MPa, the vacuum degree was higher, and a larger pressure difference was formed. The larger pressure difference caused some mechanical damage and physiological injury on Pleurotus eryngii fruit body. The cell structure was destroyed. And the normal metabolic pathway and related enzyme system were changed under the larger pressure difference condition. This storage condition finally caused that the change laws of the storage quality and the physiological and biochemical indices of Pleurotus eryngii were different from those under 0.06 and 0.04 MPa, and the concrete change law and the dominant cause needed further study. In summary, the hypobaric storage in appropriate pressure range could effectively reduce the respiration rate, and delay the ripening and senescence process of Pleurotus eryngii. The hardness, springiness, cohesiveness, chewiness and the color of Pleurotus eryngii were preferably maintained, and the storage period was effectively prolonged. But too low storage pressure would cause some damage to the Pleurotus eryngii fruit body and influence the storage effect. The concrete ultimate pressure value for hypobaric storage of Pleurotus eryngii needs to be determined by further experimental research.