Sinaphaenops (s. str.) lipoin. sp. is described and illustrated from a limestone cave in central Guizhou Province, China. This new species is most similar to S. (s. str.) banshanicus Tian, Chen and Tang, 2017. Both species are members of a peculiar species-group in the nominate subgenus Sinaphaenops (s. str.) Uéno and Wang, 1991, based on the presence of anterior lateromarginal setae on the pronotum and preapical pores on the elytra. In addition, the male genital characteristics of S. (s. str.) orthogenysUéno, 2002 are described for the first time.