The invention discloses a method and a system for preparing an amino acid fertilizer from industrial tail gas fermentation waste liquid. The method comprises the following steps: concentrating the industrial tail gas fermentation waste liquid to obtain concentrated waste liquid; carrying out hydrolysis treatment on the concentrated waste liquid to obtain an amino acid solution; and drying the amino acid solution to obtain the amino acid fertilizer. According to the method, the industrial tail gas fermentation waste liquid can be converted into the amino acid fertilizer, and trace elements suchas nitrogen, phosphorus and potassium in the industrial tail gas fermentation waste liquid are reserved, so that the resource utilization rate of the industrial tail gas fermentation waste liquid isincreased, and the sewage treatment load is reduced.