Abstract: A new diatom species, Cyclotella asterocostata is described in the paper. The species was collected from Miyan Reservoir in Beijing, Tangshan in Hebei, Shanyang in Liaoning, Suzhou in Jiangsu, Guilin in Guangxi. It is characterized by a wide marginal region, with the width of the marginal region about half of the valve radius. There are radiate rows of costa alternate with alveola on the surface of valve central region and marginal one. The species has not an isolated punctum, but has some scattered puncta, on the surface of valve central region.

Key words: Cyclotella, C.asterocostata