Based on the light and electron microscopy, we carried out a morphological study on a canalraphebearing diatom species Nagumoea africana from the Yellow Sea, China. Geographical distributions of this species were also herein discussed. The results show that: (1) N. africana frustules are rectangular in girdle view, and the valves are narrowly elliptical with broadly rounded apices. (2) The raphe is located along the valve median line and composed of two branches of equal length. (3) The raphe canal is supported by complex, anastomosing fibulae without a keel. (4) Each stria bears one areola, and a row of areolae may also be present along the mantle. (5) N. africana is now only found in the Saldanha Bay of South Africa and the Yellow Sea of China. This taxa is the first reported species of this genus in China, representing the first record of the genus Nagumoea in China.