The present study aimed to investigate the impact of heat treatment on the nutritional characteristics of fresh lotus root， considering its different varieties and growth stages. Specifically， the alterations in phenolic content， digestive features， and in vitro antioxidant capacity induced by steam heating were studied. The results showed that heat treatment led to a significant reduction in free phenols and free flavonoids in lotus roots(P<0.05)， accompanied by a decrease in DPPH free radical scavenging ability and FRAP total antioxidant capacity. Notably， high-pressure heating resulted in a greater reduction compared to atmospheric heating. Furthermore， heat treatment significantly influenced the release of phenolic compounds during simulated digestion processes of lotus root. In unheat treated samples， the average amounts of released phenolic compounds were 15.18 mg/g dw in saliva， 11.23 mg/g dw in gastric juice， and 3.18 mg/g dw in intestinal juice； whereas for atmospheric heated samples these values were respectively 9.74， 15.14 mg/g dw and 4.92 mg/g dw. The order of DPPH free radical scavenging ability was found to be gastric juice > saliva > intestinal juice； while for FRAP antioxidant ability it was saliva > gastric juice > intestinal juice. Overall， the results suggest that heat treatment can modify the nutrient properties of lotus root by influencing the digestion process and release of phenolic compounds. These findings provide valuable insights for quality control during thermal processing of lotus root.