The invention discloses a heat treatment technology for an engine shield. The heat treatment technology comprises the steps of 1) carrying out normalizing, specifically, carrying out secondary normalizing treatment on the cast-formed engine shield; 2) carrying out high-temperature tempering, specifically, carrying out heat preservation on the normalized shield in a furnace at 340-380 DEG C for 6-8 hours, carrying out high-temperature tempering to increase the temperature to 670-730 DEG C, carrying out heat preservation for 8-10 hours, gradually cooling the shield until the temperature is lower than 120 DEG C, and discharging the shield from the furnace; 3) carrying out quenching, specifically, raising the temperature of the shield to 680-720 DEG C, carrying out heat preservation for 2-3 hours, increasing the temperature to the quenching temperature of 820-880 DEG C, carrying out heat preservation for 4-5 hours, and then carrying out water cooling to the room temperature; and 4) carrying out annealing, specifically, the shield is finally heated to 380-420 DEG c, carrying out heat preservation for 8-10 hours, increasing the temperature to the annealing temperature of 660-720 DEG C, carrying out heat preservation for 10-12 hours, and carrying out air cooling to the room temperature. According to the heat treatment technology, the heating temperature is properly increased and the heat preservation time is prolonged, and therefore the structure of alloy steel of the engine shield can be fully converted, the mechanical property and the impact toughness of the engine shield can be effectively improved, and the good comprehensive mechanical property requirements of the automobile engine shield can be met.