Abstract: In order to enhance the comprehensive utilization of pomelo fruitlets, the effect of steam explosion (SE) at 0~80 s retention time on the basic composition, structural, physicochemical, and functional characteristics of dietary fiber from pomelo fruitlets was investigated. The results showed that with retention time prolonged, the yield of pomelo fruitlets dietary fiber increased from 89.25%±0.50% to 95.13%±0.60% (P<0.05). SE treatment with retention time at 20~60 s significantly increased the proportions of gluconic and galacturonic acids in dietary fiber from pomelo fruitlets (P<0.05). When the retention time was 40 s, SE treatment increased the water holding capacity, oil holding capacity and swelling capacity of pomelo fruitlets dietary fiber by approximately 5.24%, 6.86% and 57.00%, respectively; meanwhile, the glucose and cholesterol adsorption capacity, and pancreatic lipase inhibitory significantly increased by 6.77%, 61.02%, 14.53%, respectively (P<0.05), while crystallinity and thermal stability were reduced. In conclusion, there were differences in physicochemical and functional properties of dietary fiber from pomelo fruitlets with different retention times after SE treatment. When the retention time was 40 s, it had obvious advantages in some physicochemical properties such as water holding and oil holding capacities, which effectively improved its in vitro lipid-lowering ability and other functions. The results can provide theoretical reference for the high value processing and utilization of dietary fiber in pomelo fruitlets, and its development and application in functional food.