The invention relates to a preparation method and application of a 
prawn non-
specific immunity reinforcing agent 
oligopeptide. The preparation method comprises the following steps of: 
mincing pacific alaskapollack dogmeat by a meat mincer and then placing in an 
enzyme reactor to heat and sterilize; triturating and then heating to 90 DEG C to preserve the temperature; sterilizing for 20 minutes in a constant temperature water bath; adding water and 
protease preparations to mix; carrying out enzymolysis under the condition of optimized enzymolysis process parameters; then heating enzymolysis liquid so that 
protease is inactivated; roughly filtering fishbones and centrifugalizing the enzymolysis liquid to obtain a soluble 
protein oligopeptide; ultrafiltering, purifying, freezing and 
drying and then obtaining 
protein oligopeptide powder. The 
protease preparations comprise Alcalase and Flavourzyme, and the enzymolysis process parameters comprise the enzymolysis temperature of 55 DEG C, the initial pH value of 8.5, the material and water ratio of 1:1 and the enzymolysis time of 3 hours. A 
macromolecule substance is intercepted by using a method for combining 8,000rpm high-speed centrifugalization and 100kDa 
ultrafiltration membrane ultrafiltrating purification, and 30 percent of 
protein oligopeptide with the molecular weight of smaller than 100Da is obtained, the further filteration is carried out by 1kDa / 5kDa 
ultrafiltration membrane to obtain an ultrafiltrate, and the oligopeptide 
powder is obtained by freezing and 
drying the ultrafiltrate. The oligopeptide 
powder replaces 5 percent of 
fish meal in 
prawn feed and can obviously improve the 
blood corpuscle density, the phenoloxidase activity, the 
respiratory burst activity, the SOD activity, the NOS activity and the specific growing rate of a 
prawn.