Abstract: Objective To study the effect of medium-chain fatty acid（MCFA） on body weight and body fat in patients with hypertriglyceridemia complicated with different HDL-C levels. Methods One hundred and twelve patients with hypertriglyceridemia were randomly divided into MCFA triacylglycerol（MLFAT） group and long-chain fatty acid triacylglycerol（LCFAT） group.They were asked to ingest fixed energy,25-30g oil and perform physical activity daily during the whole study.Anthropometric measurement,body composition analysis,abdominal CT scanning at umbilical level,and measurement of serum HDL-C levels（＜1.04mmol/L,1.1-1.55mmol/L,≥1.55mmol/L） were performed at the beginning and 8 weeks of the study and compared. Results The body weight and body fat were significantly lower in MLFAT group（P＜0.05） while no significant difference was observed in body weight and body fat of LCFAT group 8 weeks after treatment than before treatment.No significant difference was found in the other indications except the abdominal fat area in those with HDL-C level＜1.04mmol/L（P＜0.05） between the two groups 8 weeks after treatment.The body weight,BMI and abdominal fat area were significantly lower in those with HDL-C level =1.04-1.5mmol/L than in LCT group 8 weeks after treatment（P＜0.05）.The body weight,BMI,waistline,waist-to-hip ratio,body fat,abdominal fat area were significantly lower in those with HDL-C level≥1.5mmol/L than in LCT group 8 weeks after treatment（P＜0.05）. Conclusion Rational intake of medium-and long-chain fatty acid triacylglycerol can reduce the body weight and body fat in patients with hypertriglyceridemia complicated with different HDL-C levels,especially in those with no normal HDL or HDL-C≥1.04mmol/L.