The ship airwake is a complex unsteady air flow field formed at the stern of the ship when the natural air flow passes through the ship and is blocked by the hull and superstructure. In order to create a good take-off and landing environment for the helicopter, the design of ship superstructure should not only consider the stealth and function, but also consider the ship airwake. An evaluation method of ship superstructure design for ship airwake was put forward. The force and moment exerted by the unsteady ship airwake on the fixed point of the helicopter in the flight deck airspace were measured, and the change of force and moment in 30s time was recorded. The load exerted on the helicopter by the ship airwake was represented by the integral square root (RMS) between 0.2 and 2Hz, which corresponded to the workload of the flight crew; the time average of the force and moment corresponded to the control margin of the helicopter. In addition, the ship airwake would affect the smoke exhaust of the ship"s chimney, and the temperature gradient of the flight deck airspace could be used as another index to evaluate the design of ship superstructure.