In order to investigate the effect of crosswind on helicopter ditching performance，designing of a crosswind-fan system and ditching experiment of a helicopter model were conducted , investigated the effect of blade angle and distance between fans on crosswind velocity，then investigated the effect of crosswind velocity on attitude angle，overload and bottom-pressure of the helicopter model。The results show that，the blade angle equal 18 degree is better than 15 degree and 20 degree.The crosswind velocity uniform distribution when L/D equal 1.66.The crosswind has almost no effect on pitch angle but makes the roll angle amplitude larger and more difficult to be stabilized.When the crosswind velocity increases，the overload,the bottom-pressure at the plane of symmetry and near crosswind-fan system increases，but the bottom-pressure far from crosswind-fan decreases.