A water-soluble anti-caking agent is developed according to that the ordinary anti-caking agent can not be applied to the water-soluble macroelement fertilizer.The preparation process of the water-soluble macroelement fertilizer product is introduced,and its performance is tested.The results show,the water-soluble anti-caking agent has the good anticaking effect with the anti-caking rate of 90% after 90 days,as well as some excellent characteristics including the low consumption,low cost,improving the water solubility of the fertilizer and the nutrient content.