Abstract: The effect of different precooling methods on shelf life quality of broccoli was studied in this paper. The three groups of broccoli were precooled as follows:Cold storage precooling(control),ice precooling,cold water precooling. After the temperature of broccoli centropiece decreased to(1±1) ℃,the broccoli was taken out of the box and stored in the warehouse with the temperature of(20±1) ℃. The broccoli reduced to(1±1) ℃ was taken as the initial value,and then samples were taken every 24 h for the determination of various indicators. The results showed that compared with cold storage precooling,ice precooling and cold water precooling could effectively inhibit the yellowing of broccoli and maintain its color and good sensory quality. The contents of V_C,chlorophyll and glucosinolates in broccoli was improved and stored for 4 d. The V_C contents of broccoli precooled by ice and precooled by cold water was 15.6% and 39.2% higher than that of CK treatment,respectively. The chlorophyll content was 1.87 times and 2.44 times higher than that of CK group,respectively. The increasing of conductivity and MDA contents in broccoli was inhibited. The activity of broccoli APX,CAT and POD were improved. Among them,the activity of cold-water precooled broccoli was the most significant and kept at a high level,which cleared H₂O₂ and peroxide in the body of broccoli,promoted substances in the antioxidant system,and enhanced the antioxidant capacity of broccoli. Ice precooling and cold water precooling could improve the sensory quality of broccoli,delay the aging of broccoli,and extend the shelf life for 2~3 d.