The invention relates to warm water flush fertilizer for flushing vegetables and a preparation method thereof. The warm water flush fertilizer is mixed solution which is fermented by adding organic materials and inorganic nutrients into chicken manure, and then adding in microbial agent, wherein the total content of nitrogen, phosphorus and potassium is 25 weight percent to 45 weight percent, thecontent of organic substances is 20 weight percent to 35 weight percent, and the content of amino acid is 8 weight percent to 15 weight percent. The nutrients contain comprehensive and balanced content, more beneficial microorganism and active organic substances, and play significant roles in loosening the soil, improving the soil fertility, and improving the soil microorganism environment. The warm water flush fertilizer can be adjusted by different mixing ratio for different vegetable crops in different growth periods. The nutrition is comprehensive, the matching is reasonable, the supply is balanced, and the growth needs of the vegetable crops in different periods can be met. The method has wide raw material sources, a simple production process, a convenient operation process, low production cost and significant application effect.