Adriamycin (ADM) is a widely used anticancer drug, but the chronic cardiotoxicity severely limits the use of it in the treatment of neoplastic disease. The experimental results obtained from F₁F₀-ATPase activity assay. ³¹P-NMR spectra measurement. fluorescent probe NBDPE detection. packing and fluidity of membrane lipids and intrinsic fluorescence measurements can be summarized as follows: ADM induces the phase transition of mitochondrial membrane lipids at first. as a consequence affecting on the lipid packing and fluidity of the lipid molecules and then influencing the conformation of the F₁F₀-ATPase and finally resuiting in the decreasing of the enzymatic activity. And Mg²⁺ can protect all the effects induced by ADM thus reducing the harmful effect of ADM.