Esterase isozyme zymogram polymorphisms of 56 strains in Auricularia polytricha were investigated by using vertical slab polyacrylamide gel electrophoresis. The results showed there is diversity among 56 strains. 10 zymogram bands were observed and 26 zymogram types existed in all tested strains. Each strain has 1 similar to 6 bands. Differences of strains were expressed in individual characteristic zymograms in this study. The results of cluster analysis at a 67% similarity level showed that all tested strains could be clustered into 8 groups, with the the 1st group including 34 strains, 2nd group including 21 strains, 3rd and 4th group only single strain of A. auricla and 915 respectively; 5th group including 4 strains, 6th group including 4 strains, 7th group including 2 strains, 8th group including 2 strains. The analytical technique of esterase isozyme is an effective method for identifying strains in species and under species.