Abstract： Objective： To observe the clinical efficacy of modified Wendan Decoction combined with highintensity interval training （HIIT） in treating simple obesity in adolescents of spleen deficiency and phlegm-damp type， based on conventional interventions. Methods：A total of 96 adolescents with simple obesity of spleen deficiency and phlegm-damp type treated at the Traditional Chinese Medicine Department of Anyang Maternal and Child Health Care Hospital from June 2023 to June 2024 were included as study subjects，and were randomly divided into the observation group and the control group according to the random number table method，with 48 cases in each group. Both groups received conventional interventions （diet control， exercise guidance， and daily routine correction）， while the observation group additionally received modified Wendan Decoction combined with HIIT. Both groups were treated for 12 weeks. Traditional Chinese medicine （TCM） syndrome scores were evaluated， body weight and height were measured， body mass index （BMI） was calculated， and lipid metabolism indicators [total cholesterol （TC）， triglycerides（ TG），low-density lipoprotein cholesterol（ LDL-C），and high-density lipoprotein cholesterol（ HDL-C）] were detected before and after treatment. The clinical efficacy in the two groups was compared，and a 6-month followup was conducted after the treatment period to calculate the body weight rebound rates in effectively treated patients. Results： After 12 weeks of treatment， the total effective rate in the observation group was higher than that in the control group（ P＜0.05）. TCM syndrome scores，body weight，and BMI in both groups were decreased when compared with those before treatment （P＜0.05），with the observation group showing lower TCM syndrome scores，body weight， and BMI than the control group （P＜0.05）. TC，TG，and LDL-C levels in both groups were decreased，while HDL-C levels were increased when compared with those before treatment， differences being significant （P＜0.05）. The observation group had lower TC，TG，and LDL-C levels and higher HDL-C levels than the control group，differences being significant （P＜0.05）. During the 6-month follow-up，the body weight rebound rate in the observation group was lower than that in the control group （P＜0.05）. Conclusion：Modified Wendan Decoction combined with HIIT，based on conventional interventions， can further improve the treatment efficacy for simple obesity in adolescents of spleen deficiency and phlegm-damp type. It effectively alleviates clinical symptoms，reduces body weight and BMI，corrects lipid metabolism disorders，and decreases the incidence of body weight rebound.