Abstract: The roles of peroxidase isoenzymes in classification of genus Cyathus were studied by electrophoresis.It was showed by the results that the similarity coefficient(S_c) of zymograms among groups of peroxidase isoenzyme was 0.20~0.40,and the S_c among different species was 0.30~0.57.It was also indicated that the peroxidase enzymes had less to do with geological origins of the isolates because the S_c reached 0.89~1.00.The results showed that the peroxidase isoenzymes of genus Cyathus was quite stable in the species while the zymogram dissimilarity among the groups and among species in a group was obvious.Therefore it was proven that the peroxidase enzymes might play an important role in classification of this genus.