Objective To explore the possible mechanism of Kanli Granule in improving the left ventricular diastolic function in rats with diastolic heart failure. Methods Fifty-six Wistar rats were randomly divided into sham operation group

model group

Chinese medicine group and valsartan group

with 14 rats in each group. Except for the sham operation group

the rest groups were treated with abdominal aortic constriction to make cardiac pressure overload induced heart failure model. One week after operation

Chinese medicine group were gavaged with Kanli Granule solution 6. 75 g /（ kg·d）

the valsartan group were gavaged with valsartan suspension 7. 2 μg /（ kg·d）

the sham operation group and model group were gavaged with double distilled water

1 time a day

a total intervention of 32 weeks. The changes of morphology

calcium uptake

the activity of SERCA2 a and protein expression in myocardium sarcoplasmic reticulum of all groups rats were observed. Results Compared with sham operation group

the calcium uptake rate of myocardial sarcoplasmic reticulum in model group was significantly decreased

SERCA2 a activity was decreased and SERCA2 a protein expression was increased in cardiac muscle tissue（ P < 0. 05 or P < 0. 01）; Myocardial muscle mass was significantly decreased

and the mitochondria were severely cavitation. Compared with the model group

the calcium uptake rate increased

SERCA2 a activity and protein expression were significantly increased in the Chinese medicine group（ P < 0. 05 or P < 0. 01）; Cardiac muscle sarcoplasmic reticulum and mitochondria keep good structure. Conclusion Kanli Granule can improve the left ventricular diastolic function in rats with diastolic heart failure probably by increasing the SERCA2 a protein and activity of the myocardium and promoting the calcium uptake rate of the myocardium sarcoplasmic reticulum.