In order to remit the effect of high temperature damage on tea and fruit trees, a spray cooling fan with lowpower consumption was designed. According to the structure size of arc plate fan blade, the structure of air duct on the spray cooling fan was modeled by Pro/E software. And the dynamic simulation was applied with Fluent software. The diameter of air outlet, length of air inlet and length of air outlet were selected as experimental factors. The total outlet pressure and wind speed were taken as indicators, which were obtained by dynamic simulation. DesignExpert 8.0.6 software was used to optimize the structure of air duct. Then, two types of nozzles with WJ-7010 and WJ-8010 were determined with flow test. With two nozzles, the optimized air duct was carried out to conduct wind speed test and spray cooling performance test. The optimized results showed that the order of significance was outlet diameter, outlet length and inlet length. The optimized combination was outlet diameter of 1070mm, inlet length of 350mm and outlet length of 270mm. Combined with the length of fan section of 220mm, total length of the duct was 840mm. Based on the outlet diameter of 1070mm and total length of 840mm, the outlet air volume, maximum wind speed and effective air supply distance were 701.30m3/min, 16.00m/s and 55m, respectively. The cooling performance test result showed that the average temperature was decreased by 0.68~11.11℃ and the maximum temperature difference range was 1.80~13.90℃ when WJ-8010 nozzle was used. At a high temperature of 38℃, the cooling range of spray cooling fan within a range of 0~20m was close to 5℃. This machine could relieve the high temperature stress problem of tea and fruit trees.