Abstract: The seedlings of the yellow-green leaf mutant of cantaloupe were used as test materials.Three different light intensity treatments were used to study the agronomic characters, chlorophyll content, reactive oxygen species and antioxidant enzyme activities, and chlorophyll fluorescence properties of the mutants.The adaptation characteristics of mutants to light intensity and the selection of light intensity suitable for the growth of mutants were explored, in order to provide reference for the breeding of varieties with low light tolerance.The results showed that no shading（treatment A）,the active oxygen of the mutant caused severe photoinhibition damage, while light shading increased the antioxidant enzyme activity of the mutant and alleviated the damage of active oxygen; under shading treatment, the chlorophyll content of the mutant was significantly increased compared to the wild type; compared with moderate shading（C treatment）,light shading（B treatment） significantly improved the agronomic traits of the mutant, reduced the content of active oxygen substances, increased the activity of antioxidant enzymes, and reduced the destruction of photosynthetic structure.In summary, the mutant had higher chlorophyll content, less active oxygen accumulation, less membrane lipid peroxidation and plasma membrane damage under shading（B treatment）,and high PSⅡ reaction center activity and electron transfer ability, which was beneficial to plant growth.