A new species from Guangxi Province, Impatiens cornutisepala S. X. Yu, Y. L. Chen & H. N. Qin, is described for the Balsaminaceae in China. It is similar to I. dicentra Franchet ex Hooker f. in the 1-flowered peduncle and the lobes of the lateral united petals that are terminated by a long filamentous bristle. However, the new species differs from the latter in its narrowly elliptic to oblanceolate leaf blade, the smaller lateral sepals with entire margins and a prominent green cornute appendage dorsally, the spur of the lower sepal that is entire at the tip, and its differing leaf epidermis micromorphology. The micromorphology of seeds and pollen under SEM is presented.