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) LangeBertalot and Eucocconeis laevis (strup) LangeBertalot. Those two species were observed using LM and SEM, and taxonomic characters and habitat were described.