The genus Sinotrisus Yin & Li, comprising four species, is redefined and revised. Members of Sinotrisus are often found with ants of the subfamily Formicinae, or in humid forest habitats. The type species and three new species are (re-)described and illustrated: S. kishimotoi Yin & Nomura, sp. n. (China: Sichuan), S. nomurai Yin, Li & Zhao (type species) (China: Zhejing), S. sinensis Yin & Nomura, sp. n. (China: Sichuan) and S. vietnamensis Yin & Nomura, sp. n. (Vietnam: Lai Chau). A key is included as an aid to distinguishing these species.