The experimental study on the performance of two heat exchangers (model 12-2.2/18, manufactured by Dalian Refrigerator Co., Ltd.) is made in this paper. The two heat exchangers, one is with conventional metal surface, the other is with high hydrophobic surface are contrasted in a jacket type laboratory. Under the dry and wet operating condition and at the vaporizing temperature of 0°C and -5°C, the parameters such as the refrigeration output, the heat transfer coefficient and the velocity of airflow in the airside of the finned tube bundles are measured. The experimental results show that high hydrophobic coating can improve the heat transfer performance of air cooler especially at the wet operating condition and decrease the frost temperature on the cold surface. The theoretical analysis of the mechanism of the drop condensation on the hydrophobic surface is also given in this paper.