Togeta more accuratemodel ofcutting powerand improve the ability of evaluating energy consumption of machine tool and energy optimization, this paper takes face milling for example, chooses gray cast iron as the work-piece material, adopts four factors (spindle speed, feed rate per tooth, milling depth and milling width) and four levels orthogonal experiment and carries out cutting experiments ina machining center, obtains the cutting power by the power data acquisition device.The experimental results and model accuracy assessment show that when the coating milling cutter of W400F-FS cuts HT250 gray cast iron, specific energy and empirical formula of cutting force calculate cutting power with the average relative error of 16.06% and 32.63%respectively, but the fit cutting power model with the average relative error of 3.7% is achieved by SPSS software. The problem of calculating cutting power through specific energy and empirical formula of cutting forcewith much error is solved.