Objective： This study aimed to solve the problems of yellowing, discoloration and quality preservation of broccoli after harvesting. Methods： Broccoli was fumigated with chlorine dioxide gas at different mass concentrations (0,0.2, 0.5, 1.0, 1.5, 2.0 mg/L) at 23 ℃, and the sensory, color, yelination grade, physiological and biochemical indexes and related browning enzyme activities of broccoli were determined after 0,2,4,6,8 days of storage. Results： Compared with the control group, different mass concentrations of ClO₂ could inhibit the mass loss rate, yellowing browning and spoilage of flower buds of broccoli. ClO₂ at 0.5 and 1.0 mg/L had a more significant effect on the maintenance of chlorophyll content, color difference a^* and b^*, and the inhibition of PPO and POD enzyme activities in broccoli. Among them, 0.5 mg/L ClO₂ had the best effect on maintaining the color difference value of broccoli flower buds, and the yelination grade was still grade Ⅱ on the 8th day of storage. Simultaneously, it effectively maintained the vitamin C content and delayed the yelination and Browning of flower buds. Conclusion： It is necessary to control the concentration of ClO₂ gas in the fumigation treatment of broccoli to obtain the best effect of maintaining the fresh green of broccoli bulbs and extending the shelf life.