An analytical method is developed for computing shipborne helicopter′s l anding flowfield based on steady NavierStokes equations, which can effectively b e used to analyze the flowfield interactionamong rotor, fuselage and shipduring l anding. In the method,the secondorder upwind scheme is employed in the spati al discretization, and a pressurevelocity coupling method is selected in the so lu tion. The adaptive trimmed grid generation method is used to generate the comput ational regions, and the rotor is replaced by a momentumsource item. A boundar y condition is added into the calculation of landing flowfield to describe the ir regular sea wind motion. In order to verify the developed method, an isolated sh ip and an interaction between rotor and fuselage are taken as examples, and the calculated values are compared with the available experimental data. Then, the coupled interaction between rotor downwash and the ship flowfield is d eeply analyzed. Results show that the influence of hangar wake vortex along deck length direction is about three times the height of hangar. Opening the hangar d oor is safer for the landing process of helicopter from the perspective of aerod ynamics.The blade tension decreases first then increases and the body resistance decreases at first and finally becomes negative during the helicopter landing p ro cess.