Abstract: Uniformity experiment of temperature field for differential pressure pre cooler of top air supply type was carried out.Experiments of pre cooling efficiency and power consumption were done according to visual analysis method.Results showed that effects on pre cooling efficiency and power consumption factors from high to low were air temperature，height of stack and wind speed.Temperature uniformity of width direction，left and right direction，up and down direction were determined.Test results showed that temperature uniformity could meet the requirement of design and this machine could achieve the purpose of rapid precooling.