Abstract: Objective：To inquire into the diagnostic value of electronic microscope in cellular uterine leiomyoma. Methods：To select tissue specimen of common leiomyoma（n=10）and cellular leiomyoma（n=11），which diagnosed by optical microscope，and to observe by electronic microscope separately. Results：The myofilaments，dense bodies and dense spots were very abundant in cytoplasm both of them，but in cellular leiomyoma，the arrange of cell was disorder and the shape of cell was unregular. The mitochondria，rough endoplasmic reticulum， cytolysosomes，golgiosomes in cytoplasm were increase obviously. The nucleolus was big and atypia. There were false inclusions in nucleolus. Conclusions：The ultrastructures were different between cellular and common leiomyoma. The metabolism of cellular leiomyoma was brisk and lack differentiation to a certain degree.

Key words: Uterus, Leiomyoma, Cellular leiomyoma, Common leiomyoma, Microscopy, electron