Objective To investigate the effect of Buyang-Huanwu decoction on left ventricular diastolic function in DHF rats.Methods Thirty male Sprague-Dawley rats were randomly divided into the normal group (n=10),the Chinese medicine group (n=6),the western medicine group (n=6) and the model group (n=6).Except for the normal group,the other groups got abdominal aorta stenosis.After 12 weeks,The Chinese medicine group was given Buyang-Huanwu decoction 12.72 g/(kg·d),and the western medicine group was given metoprolo 1 0.004 5 g/(kg·d),and the normal group and the model control group were given water.After once daily for 8 weeks,echocardiography was used to measure EF,E/A ratio and e/a ratio.The heart rate,left ventricular diastolic pressure,left ventricular end-diastolic pressure,tension and maximal change in pressure of left ventricular were measured by Langendorff.Results Compared with the model group,the e/a value (1.11 ± 0.28 vs.0.67 ± 0.20) of the Chinese medicine group significantly increased (P＜0.05),and the ventricular muscle tension (0.86 ± 0.64 g vs.1.01 ± 0.33 g) significantly decreased (P＜0.05).Conclusions Buyang-Huanwu decoction could improve cardiac relaxation by reducing ventricular muscle tension,thus improving diastolic function of diastolic heart failure rats.