A method for determining a heating load of a hybrid electric vehicle includes determining an SOC of a high-voltage battery through a controller, determining whether or not there is a heating request, based on a travel pattern input, through the controller when the SOC of the high-voltage battery is normal, calculating a required heating load according to the travel pattern input when there is the heating request, calculating an environmental condition according to an environment of the vehicle when there is the heating request, calculating a final heating load value through a combination of the calculated required heating load and the environmental condition of the vehicle, and adjusting a basic request engine torque according to the travel pattern input, taking into consideration the calculated final heating load value, and controlling driving of an engine based on the adjusted basic request engine torque.