The invention relates to a method for preparing animal blood plasma albumen powder, which comprises a process system consisting of animal blood anticoagulant treatment, blood refrigeration, centrifugal separation, membrane concentration, spray drying and tail gas recycling. The method comprises the following steps of: performing anticoagulant treatment on the fresh animal blood with a compound anticoagulant liquid, refrigerating, performing centrifugal separation on the refrigerated product and obtaining blood plasma liquid; performing membrane concentration on the blood plasma liquid, allowing the obtained product to flow to a tail gas recycling device for spray drying, and absorbing blood plasma albumen powder and afterheat in the dry tail gas; performing micropore filtration and spray drying, and obtaining the high-quality animal blood plasma albumen powder. Waste gas generated by the treatment of the tail gas recycling device is directly discharged into the air. The process method reduces the ash content of the animal blood plasma albumen powder from 12 percent to 8 percent, removes odor and increases the spray drying recovery rate from 98 percent to 99.5 percent, so that resources are saved, drying energy consumption is reduced, and the risks of polluting environment are reduced.