Chamaelirium jiuwanshanense, a new dioecious species of Melanthiaceae from Jiuwanshan National Nature Reserve, Guangxi, China is described and illustrated. It is similar to C. shimentaiense, but can be clearly distinguished from the latter mainly by its dioecious sexual system, linear-lanceolate bract-like cauline leaves, racemes with pedicelled flowers, etc. A detailed morphological description, and the information on its distribution, habitat and conservation status are provided here.