In order to reveal the differences among the dimorphic cells, basidiospores, arthrospores and mycelia of Tremella fuciformis were subjected to microscopical observation and electrophoresis analysis. Morphology and nucleus phase showed that arthrospores are larger than basidiospores in diameter, basidiospores are mononuclear cells, the majority of arthrospores are dikaryocytes and the mononuclear cells are in minority, mycelia are dikaryocytes with typical clamp connection. The whole protein and isozyme analysis indicated that the mycelial form contains more bands than that of yeast form and some differences in peroxidase and esterase between the two forms were found, while the polyphenol oxidase are almost similar. Therefore, corresponding changes in metabolism level are occurred during the form transition of the dimorphic cell in T. fuciformis.