判断小细胞肿瘤的组织类型是病理活检诊断中的一个难点，电镜观察有助于诊断。本文是根据作者本身的工作，结合文献资料，对２０多种小细胞肿瘤的超微结构作了介绍，也提到肿瘤细胞的细胞器及包含物的特点在电镜诊断上的意义。 Small cell tumor tissue to determine the type of biopsy diagnosis is a difficult point, electron microscopy is helpful in the diagnosis. This article is based on the author’s own work, combined with the literature, the ultra-microstructure of more than 20 kinds of small cell tumors were introduced, but also mentioned the characteristics of tumor cells organelles and inclusions in electron microscopy diagnosis significance.