The pyrolysis gas chromatography of 29 strains nuclear polyhedrosis viruses, 11 strains cytoplasmic polyhedrosis viruses and 16 strains granulosis viruses were performed on a shimadzu GV-9A capillary gas chromatography equipped with a pyrolyser model PYR-2A. The differences among the inclusion bodies of NPV, CPV and GV could clearly be distinguished and also beidentified through analysis of fingerprinting the hierarchical clustering analysis of GC, This procedure has provided a usefel method for the classification and identification of viruses.