In order to achieve the long-distance transportation of leafy vegetables at room temperature,the effect of CO 2 with different concentrations(0,3%,6%,9%,12%,15%,18%) on the storage quality of Bok choy at room temperature(20 ± 1℃) was investigated.The results showed that with the extension of storage time,chlorophyll content,Vc content and reducing sugar content were decreased,yellowing index and the weight loss were gradually increased,and soluble solids content increased first and then decreased.At the eighth day of storage,the weight loss rate of each treatment was not significant;Chlorophyll content and yellowing index with CO 2 were smallest;Vc content,soluble solids content and reducing sugar content with the treatment of 9% and 12% CO 2 was significantly higher than other treatments and Bok choy still had market value at room temperature after 6d.