Abstract: In order to clarify the fresh- keeping effect of pretreatment with hypobaric action in stored Tricholoma matsutake, Tricholoma matsutake was treated with different pressure ( 1500 Pa, 800Pa) and time ( 36 h, 48h) , then put in the ordinary cold storage ( 2 ± 0.5℃) .At the same time, peroxidase activity, polyphenol oxidase activity, catalase activity, superoxide dismutase activity, soluble protein and free amino acid content were determined respectively.The results showed that three kinds of hypobaric pretreatment could inhibit PPO activity of Tricholoma matsutake storage process, keep POD, CAT, SOD activities a higher level and delay the degradation of soluble protein and the increase of free amino acid content, which was good for extending the freshness of Tricholoma matsutake.Pretreatment effect with 1500 Pa and 48 h was better than others.