A method of accurately predicting energy consumption of an automatic tool change process is described. Automatic tool change durations at a plurality of groups of rotary tool position numbers are measured and a calculation model of the automatic tool change duration is obtained. A basic module power of machine is obtained. A basic module energy consumption of machine is obtained by calculation based on the basic module power of machine and the automatic tool change duration. A steady state power of tool changer is obtained. A steady state energy consumption of tool changer is calculated. A transient state energy consumption of tool changer is obtained by accumulating energy consumptions. An energy consumption prediction model of the automatic tool change process is obtained using the obtained basic module energy consumption of machine, the obtained steady state energy consumption of tool changer, and the obtained transient state energy consumption of tool changer.