Abstract: Objective: To explore the dose-effect relationship of n-butanol extracts of Amygdalus mongolica on reducing blood lipid and study the chemical constituents of the n-butanol extracts of Amygdalus mongolica. Methods: Kernels of Amygdalus Mongolica was extracted by n-butanol to get the n-butanol extracts. Wistar rats were randomly assigned into two weight balanced groups: the blank control group and the model group. The blank control group was fed with general diets,the model group was fed with high fat diets to build hyperlipemia model.After the models were successfully built,keeping in accordance with the above feeding methods,Wistar rats were divided into four treatment groups: the blank control group,the model group,the positive drug group( Simvastatin) and the different doses of n-butanol extracts treatment group. The blank control and the model group were treated with physiological saline by intragastric administration,the different doses of n-butanol extracts treatment group were treated with 0.25,0.5,1.0,2.0,4.0 g / kg n-butanol extracts by intragastric administration respectively.After seven weeks of administration,the contents of total cholesterol( TC),triglyceride( TG),high-density lipoprotein cholesterol( HDL-C) and low-density lipoprotein cholesterol( LDL-C) were determined. N-butanol extracts of Amygdalus mongolica were separated and purified by chromatographic and spectroscopic methods. Results: Comparing to hyperlipemia model,0.25,0.5 g / kg and 4.0 g / kg n-butanol extracts didn't show significant effect of reducing blood lipid,while 1.0 g / kg and 2.0 g / kg n-butanol extracts could significantly reduce the contents of TC and LDL-C( p < 0.05),and the effect of2.0 g / kg n-butanol extracts was the best; amygdalin was isolated from n-butanol extracts of Amygdalus mongolica.Conclusion:The dose of n-Bu OH extracts being effective ranged from 1.0 g / kg to 2.0 g / kg,and the dose of 2.0 g / kg n-Bu OH extractsshowed best effect.Amygdalin was isolated from kernels of Amygdalus mongolica for the first time.