Abstract: 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 vannameihave 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.