The invention discloses a method based on energy change for evaluating an emergency control measure improvement transient frequency safety contribution degree and belongs to the electric power system operation control technology field. The method comprises steps that based on electromechanical transient time domain simulation, in combination with a frequency safety two-element table, emergency control measure improvement transient frequency safety conditions are analyzed and classified to acquire typical periods of emergency control measure improvement transient frequency safety characteristics, accumulation energy of control object output power is calculated through analysis on the periods, for considering importance difference of the different periods, contribution of a single control measure for a single frequency safety two-element table constraint improvement transient frequency safety is acquired, a comprehensive contribution of the emergency control measure improvement transient frequency safety is further acquired, and lastly, a relative contribution degree of each control measure is analyzed and calculated. The method is advantaged in that the emergency control measure improvement safety stability degree is reasonably evaluated, and the method plays an important role in emergency control influence coordination and power grid safety and stability.