The invention discloses a method for preparing highly-unsaturated fatty acyl propanolamine through a one-pot method. The method comprises the steps of sequentially adding algal oil glyceride, propanolamine, triethylamine and a KOH (potassium hydroxide) reaction liquid into a reaction bottle; performing heating reflux by using the one-pot method to directly prepare a highly-unsaturated fatty acyl propanolamine compound; performing normal pressure silica-gel column chromatography separation to ensure that the total content of the product namely the highly-unsaturated fatty acyl propanolamine compound is more than 96%. The method disclosed by the invention has the advantages of short preparation route, simple process, convenience in operation, mild reaction conditions and low preparation cost, and is an efficient and convenient method for preparing highly-unsaturated fatty acyl amide compounds.