The invention belongs to the technical field of 
biomedicine, and particularly relates to a preparation method of 
fusobacterium nucleatum 
neutrophile granulocyte activator 
protein. The preparation method comprises the following steps of 1, culturing 
fusobacterium nucleatum, specifically, taking out a bacterium 
cryopreservation tube, placing the bacterium 
cryopreservation tube on ice, dissolving, inoculating an Fn strain on a blood plate, and culturing at 37 DEG C for 48-72 hours under extremely anaerobic conditions; step 2, extraction of 
bacterial DNA, specifically, scraping a proper amount ofFn bacterial colonies in a good growth state, placing the Fn bacterial colonies in a 1*PBS 
buffer solution, and extracting bacterial 
genome DNA; and step 3, NapA 
gene amplification, specifically, taking Fn 
bacteria DNA as a template, and carrying out the amplification according to the following condition that a 
reaction system is 50 [mu] L. The Fn NapA 
protein has a plurality of high-antigenicitypeptide fragments, has good 
antigenicity, has a small cross-
immune reaction with human intestinal 
symbiotic bacteria, and has a good development prospect in Fn vaccine candidate antigens.