A preparation method for low-ash poultry plasma protein powder, wherein the method includes the following steps: (a) Mixing the poultry blood with anticoagulant, so as to obtain anti-coagulated whole blood; (b) Centrifuging the anti-coagulated whole blood obtained in step (a) to collect the light liquid, so as to obtain the plasma liquid; (c) Adding decalcifying agent into the plasma liquid obtained in step (b), and conducting precipitation reaction, so as to obtain precipitated plasma reaction liquid; wherein the decalcifying agent comprises a water-soluble carbonate; and the amount of added decalcifying agent is 0.02 - 0.5% (w/w) of the plasma liquid obtained in step (b); (d) Removing the precipitate by centrifuging the plasma reaction liquid obtained in step (c), so as to obtain the decalcified plasma liquid; (e) Ultrafiltration-processing the decalcified plasma liquid obtained in step (d) using an ultrafiltration membrane, and collecting the filtrate, so as to obtain ultrafiltration-processed plasma liquid; wherein the ultrafiltration membrane is an ultrafiltration membrane with molecular weight of 300,000-500,000; (f) Adding emulsifier to the ultrafiltration-processed plasma liquid obtained in step (e), so as to obtain the emulsified plasma liquid; wherein the amount of added emulsifier is 0.01 - 0.5% (w/w) of the plasma liquid obtained in step (e); and the emulsifier is selected from: fatty acid monoglyceride, sorbitol ester, soybean phospholipid, or a combination thereof; (g) Subjecting the emulsified plasma liquid obtained in step (f) to nanofiltration to obtain a plasma concentrate; wherein the nanofiltration is performed using a nanofiltration membrane with molecular weight of 200-1000, the volume ratio of plasma concentrate to filtrate is 1: 2 - 4, and the plasma concentrate is collected; (h) Drying the plasma concentrate obtained in step (g), so as to obtain poultry plasma protein powder. (a) Mixing the poultry blood with anticoagulant, so as to obtain anti-coagulated whole blood; (b) Centrifuging the anti-coagulated whole blood obtained in step (a) to collect the light liquid, so as to obtain the plasma liquid; (c) Adding decalcifying agent into the plasma liquid obtained in step (b), and conducting precipitation reaction, so as to obtain precipitated plasma reaction liquid; wherein the decalcifying agent comprises a water-soluble carbonate; and the amount of added decalcifying agent is 0.02 - 0.5% (w/w) of the plasma liquid obtained in step (b); (d) Removing the precipitate by centrifuging the plasma reaction liquid obtained in step (c), so as to obtain the decalcified plasma liquid; (e) Ultrafiltration-processing the decalcified plasma liquid obtained in step (d) using an ultrafiltration membrane, and collecting the filtrate, so as to obtain ultrafiltration-processed plasma liquid; wherein the ultrafiltration membrane is an ultrafiltration membrane with molecular weight of 300,000-500,000; (f) Adding emulsifier to the ultrafiltration-processed plasma liquid obtained in step (e), so as to obtain the emulsified plasma liquid; wherein the amount of added emulsifier is 0.01 - 0.5% (w/w) of the plasma liquid obtained in step (e); and the emulsifier is selected from: fatty acid monoglyceride, sorbitol ester, soybean phospholipid, or a combination thereof; (g) Subjecting the emulsified plasma liquid obtained in step (f) to nanofiltration to obtain a plasma concentrate; wherein the nanofiltration is performed using a nanofiltration membrane with molecular weight of 200-1000, the volume ratio of plasma concentrate to filtrate is 1: 2 - 4, and the plasma concentrate is collected; (h) Drying the plasma concentrate obtained in step (g), so as to obtain poultry plasma protein powder.