The genus Ischnothyreus Simon, 1893 is one of the most speciose genera of Oonopidae , with 114 extant species mainly distributed in the Old World. Currently, 16 species have been recorded in China.
Two species of the genus Ischnothyreus Simon, 1893 from China are recognised, including one new species, I. yunlong Tong & Li, sp. n. (male, female) from Yunnan. Ischnothyreus yueluensis Yin & Wang, 1984 is re-studied. Descriptions, diagnoses and photos of the two species are provided.