本文用电镜技术对２０例不同胚龄人胃底粘膜ＡＰＵＤ细胞进行了超微结构的研究。发现胚胎第８周，在粘膜上皮细胞间就已出现了ＡＰＵＤ细胞，具有基底颗粒形态，早于其他学者的报道。我们将胚胎期ＡＰＵＤ细胞分为５种类型，即：前Ｄ１、前Ｄ，前ＥＣＬ、ＥＣ和前Ａ细胞。各种类型的细胞和成长期的同类细胞又稍有不同，出现的时间不一。并从超微结构的角度对胚胎期各种ＡＰＵＤ细胞做了详细的描述，分析和探讨了它与肿瘤的关系，为临床ＡＰＵＤ瘤的鉴别与诊断提供了形态学依据。 In this paper, electron microscopy was used to study the ultrastructure of APUD cells from 20 different embryonic ages. It was found that APUD cells appeared in the epithelial cells of the epithelium at the 8th week of the embryo and had a basal granule morphology earlier than other scholars reported. We divided embryonic APUD cells into five types: pre-D1, pre-D, pre-ECL, EC, and pre-A cells. Different types of cells and growth-like cells are slightly different, and they have different time. From the ultrastructural point of view, various APUD cells in the embryonic stage were described in detail, and the relationship between it and the tumor was analyzed and discussed, which provided morphological basis for the identification and diagnosis of clinical APUD tumors.