The invention relates to the technical field of preparation of veterinary medicine and provides a method for preparing novel metabolic accelerator butafosfan. The method includes using n-butylamine, acetone, hypophosphorous acid as raw materials, condensating the n-butylamine and the acetone to generate imine, and reducing by hypophosphorous acid. Specifically, the method includes the steps of adding the n-butylamine and the aceton into a reactor, stirring at room temperature, dropping hypophosphorous acid into the acetone solution, controlling the reaction temperature within 40 DEG C; cooling and filtering after backflow reaction, and centrifuging to obtain crude products; adding the crude products into a crystallizing reactor, adding the acetone/methyl alcohol solution, heating to backflow, cooling, centrifuging and drying to obtain finish products. The method for preparing novel metabolic accelerator butafosfan is low in material cost, short in steps, high in operability, low in pollution and high in yield, and the total yield of target compounds is 90% around.