【Objective】 In order to distinguish very-virulent strain,virulent strain and vaccine strain,the conserved reign of conservative sequence in IBDV VP2 gene was digested by different pairs of restriction enzymes.【Method】 One pair of primers was designed by the conserved reign of conservative sequence in IBDV VP2 gene.Nucleic acid extracts from vv IBDV GX8/99,isolation strain of Shaanxi,V IBDV strain XZ-1,ZZ-1,JL,GX-2,JS-2、SD-1、SD-3、HeN-4、ZJ-1、JX-2、JS-30 and vaccine strain B87,NF8 were used as templates for RT-...