The work aims to study the effect of low-intensity white LED irradiation on quality of postharvest Lactuca sativa. The white LED light (light intensity approximates to 5 μmol/(m2•s)) was used to continuously irradiate the Lactuca sativa at (20±1)℃ for 7 days. The samples stored in dark environment were used as control to determine the change of sensory score, decay rate, respiratory rate, content of chlorophyll, vitamin C, malondialdehyde (MDA), activity of polyphenol oxidase (PPO), catalase (CAT), and chlorophyll degrading enzymes (chlorophyllase, Mg-dechelatase, chlorophyll-degrading peroxidase, and pheophytinase). Compared with the control, LED treatment could effectively maintain the appearance quality of Lactuca sativa, inhibit the increase of respiratory rate and MDA content, keep the contents of chlorophyll, vitamin C and total phenolics, increase antioxidant enzyme activity, and reduce chlorophyll degrading enzyme activity during storage. LED treatment can delay postharvest senescence and maintain sensory and nutritional quality of Lactuca sativa by inhibiting the respiration and chlorophyll degradation rate, maintaining non-enzymatic antioxidant content and antioxidant enzyme activity and keeping cell membrane integrity.