Primulina nymphaeoides, a new cave-dwelling species of Gesneriaceae from the limestone region of southwestern Guangxi, China is described and illustrated. Morphologically, it is most similar to P. longzhouensis, but differs by having some easily distinguished characteristics, for example different leaf blade indumentum, obviously fewer flowers on one cyme, bigger flower size, and different stigma shape, and so on. Furthermore, the phylogenetic analysis of two DNA region ITS and trnL-F sequence including 179 taxa of Primulina s.l. has been provided. Both Bayesian inference (BI) and maximum likelihood (ML) analyses show the similar supported tree topology, indicating that P. nymphaeoides is recovering as one of species in a phylogenetic polytomy closed to P. longzhouensis and other species. A Global Species Conservation Assessment classifies P. nymphaeoides as Critically Endangered (CR).