Through air exhausting by fan,producing negative pressure in the cooler,and at the same time water pump transports water to the water distributor,the surface of wet curtain is full of water.Moreover,for the special angle of wet curtain,water flows directly to the side of air inlet,absorbing a lot of quantity of heat in the air when the hot air is through the wet curtain full of water,reducing the air temperature through wet curtain,and filtering the air,making the wind blowing cool,humid and fresh.The water not evaporated falls back to the sole plate,forming water route cycle.