In the observation of diatom samples from Jiuzhaigou Valley Natural Reserve. two species of Eucocconeis (Bacillariophyta) are new records of China. They are Eucocconeis alpestris (Brun) LangeBertalot and Eucocconeis laevis (strup) LangeBertalot. Those two species were observed using LM and SEM, and taxonomic characters and habitat were described.