An experiment was carried out with the objective of evaluating the effect on postharvest physiology and enzyme activities of Agaricus bisporus of ‘W2000’,with ClO₂ treatment in lowtemperature storage.This study produced the following results:with ClO₂ treatment and storing at 0℃,respiration rate drops obviously,and the arrival of respiratory climacteric has been postponed,decreased 29.2% and delayed 5 d;Enzyme activities of PPO and POD were significantly suppressed in ClO₂treated mushrooms,and restrained the accumulation of phenolic oxidation products,as well as slowing the browning rate of fruiting body.Stored 20 d,total phenolic content was only 0.81 μmol/mg.Besides,impregnating with ClO₂ could slow the decreasing speed of hardness of fruiting body,helps soluble solids content to be well maintained,while retarding the cap opening.ClO₂ treatment could effectively extend the storage period,maintain the high quality.Therefore,the commercial value of mushrooms has been greatly improved.In conclusion,the handling of dipping mushrooms in 120 mg·L^-1 ClO₂ solution and stored at 0℃ is very useful in keeping A.bisporus of ‘W2000’ fresh.