Spiradiclis tubiflora, a new Rubiaceae species, is described from a limestone area of southern China. It is similar to Spiradiclis glandulosa and S. umbelliformis, but differs from the latter two in its linear stipule, short peduncle and tubular-funnelform corolla with a distinctively enlarged tube. The colour photograph, illustrations, detailed descriptions and conservation status of the new species are provided.