As for the characteristics of nonlinear and inhomogeneous airflow field, rotor disk is divided into elements by the method of spatial dis cretization. Local speed of flow field is superimposed to the element relative flow, the calculation model of element aerodynamic force is improved, and the c alculation precision of rotor loads is increased. The airflow field on the deck is calculated by CFD method, and the downwash airflow is the key influence factor on h elicopter safety. Taking UH60A helicopter for example, the trim values of heli c opter in hover are calculated in four landing zones on flight deck. By contrast wit h the results in groundbased condition, the influence and the causation of ai r flow field on hover characteristics are analyzed. In addition, the helicopter fl ight response in airflow field on the deck is also calculated and compared with the response in MIL models, which proves the proposed model. 