In order to study the peritrophin function of Litopenaeus vannamei related to IHHNV invasion,the full-length cDNA library from intestinal tissue of Litopenaeus vannamei was constructed by switching mechanism at 5′ end of the RNA transcript technique(SMART),a full-length cDNA of peritrophin was obtained by gene splicing and its haracterization was analyzed.The capacity of constructed library was up to 1.05×10⁶ pfu/mL,and its recombinant coefficient was 95%.1 600 clones selected randomly were sequenced,1 531 available sequences with inserted length ≥450 bp were obtained after removing vector.One cDNA of peritrophin gene sequence of 1 002 bp was obtained from the clones,its protein encodes 303 amino acids.The nucleotide sequences of Litopenaeus vannameihave an overall similarity of 80% to peritrophin 1,2 precursor and peritrophin 3 precursor of Penaeus monodon.Expression of peritrophin gene in different tissue was analyzed by semi-quantitative reverse transcription PCR(RT-PCR),the result showed that the expression of peritrophin transcript in myocardium and gastric was higher,the expression was lower in hepatopancreas,intestines and muscle,the minimal expression was in gills,but not in eyes; Expression was obviously weakened in heart of IHHNV injected Litopenaeus vannamei,expression was lower in hepatopancreas,eyestalk,muscle and gills tissues,there was almost no expression in intestines and stomach.These results suggest that peritrophin of Litopenaeus vannamei was involved in prevention of IHHNV invasion.