The invention discloses a water-soluble fertilizer containing amino acid. The amino acid-containing water-soluble fertilizer comprises fermentation ingredients, amino acid liquid, rare earth and fat,the fermentation ingredients comprise, by mass, 3%-5% of starch, 5%-10% of brown sugar and 1%-2% of EM bacteria, the mass ratio of the amino acid liquid is 50%-60%, and the amino acid liquid comprisesamino acid, microelements, nitrogen, phosphorus and potassium; wherein the trace elements comprise zinc, boron, magnesium, fulvic acid and black humic acid, the amino acid accounts for more than or equal to 20% of the weight of the amino acid liquid, the trace elements account for more than or equal to 36% of the weight of the amino acid liquid, the mass sum of nitrogen, phosphorus and potassiumaccounts for more than or equal to 20% of the weight of the amino acid liquid, and the mass percentage of rare earth is 0.1%-0.5%. The amino acid water-soluble fertilizer is prepared by adopting a fermentation mode, wherein the fermentation temperature is 30 DEG C and 40 DEG C, and the fermentation time is 72 hours and 144 hours. According to the invention, the soil environment is improved, the quantity of effective microbial communities in soil is increased, the granular structure and the water retention capacity of soil are increased, the immunity of crops is improved, and the quality difference rate of products is increased.