Climacocystis was a monotypic genus typified by C. borealis. During a continuous survey of poroid basidiomycetes over China, several specimens of a Climacocystis species were collected at high elevations in southwestern China. They deviated from the type species, C. borealis in several microscopic features, including larger and ellipsoid to subcilindrical basidiospores (6-8.8 × 3-4.2 µm versus 5-6.8 × 3.2-4 µm), smooth cystidia (incrusted in C. borealis) and regularly arranged contextual hyphae (interwoven in the type species). Furthermore, phylogenetic inferences based on a combined dataset of ITS, nLSU-rDNA and EF1α regions revealed that our specimens and specimens of C. borealis formed two distinct lineages. We therefore concluded that our chinese collections represent a new species, described below as Climacocystis montana sp. nov. Illustrated descriptions of the two Climacocystis species are provided.