Rhododendron microcarpum R.L. Liu & L.M. Gao sp. nov. is described as a new species which is confined to Jiangxi, China. It has been discovered only in Yingpan Mountain located in the junction area of Nanling Mountains and Luoxiao Mountains. Morphologically, R. microcarpum is significantly distinguishable from closely related species R. ovatum by elliptic leaves with small size of 2.56 (+/- 0.11) x 1.25 (+/- 0.04) cm, pink-white corolla, short calyx with 0.23 (+/- 0.003) cm in length, and small flower and fruit. ITS Neighbor-joining (NJ) tree indicates that R. microcarpum represents a distinct species and is genetically closest to R. ovatum. Evidences from morphological, ecological and molecular data supported R. microcarpum as a new species of R. subgenus Azaleastrum Planch..