Hierarchical clustering analysis have been done on 48 strains of the representative insects inclusion body viruses (26 strains of nuclear polyhedrosls viruses, 13 strains of granulosis viruses and 9 strains of cytoplasmic polyhedrosis viruses) by capillary gas chromatography, using the eight strategies of hierarchical clustering of Euclidean distance coefficient. A comparison between the dendrograms obtained by these strategies has been made. The results showed that there are definite discriminations between baculovirus group (genus) and cytoplasmic polyhedrosis virus group (genus). The relationships among the genera, groups, subgroups and strains could clearly be unfolded. The similarities and differences among strains also be distinguished. The average method, flexible method （β=0.00）, and group average method in eight strategies of hierarchical clustering had the advantage of other strategies.
