At present, there is no systematic method to make an evaluation for airflow field design of ship superstructure. A quantitative evaluation method for airflow field design of helicopter ship superstructure is proposed. It is to calculate the time course of force and moment applied by unsteady airflow on ship-borne helicopter, to quantify the pilot control load with the integral square root of force and moment, to quantify the ship-borne helicopter control margin with the time average of force and moment, and to take the temperature change or change rate of take-off and landing platform airspace as a design evaluation index. The applicability of the method in engineering is verified with the instances.