Objective To observe effects of L-carnitine supplementation on left ventricular dysfunction in HD patients. Methods All the selected patients were randomly distributed into group A treated with benaprio and group B treated with benaprio and L-carnitine. we observed the cardiac structures and functions of the patients in two groups before and after the treatments. Results The left ventricular systolic and diastolic function and left ventricular mass index(LVMI) of the two groups were improved after the study,but only the left ventricular systolic function of the patients in group B were significantly improved compared to group A. Conclutions L-carnitine supplementation could improve left ventricular systolic function, but could not improve left ventricular diastolic function and LVMI. 