A new species of the genus Synersaga Gozmány, Synersaga atriptera Xu & Wang sp. nov. (Lepidoptera: Lecithoceridae) is described from China. Adults, wing venation and male genitalia are illustrated. The new species is similar to S. nigriptera, but is distinguished by the wing venation and the male genitalia. The ground color of wings of S. atriptera sp. nov. is darker than that of the wings of S. nigriptera, especially the hind wings; the forewing of S. atriptera sp. nov. has a broad and blackish transverse outer line, which it is not present in S. nigriptera; and the fringe of S. nigriptera has a paler basal line, which it is not obvious in S. atriptera sp. nov. Juxta of S. atriptera sp. nov. has a pair of claviform lateral lobes, which are separated at the base. Juxta of S. nigriptera also has a pair of claviform lateral lobes, but they are connected at the base by a heavily sclerotized band. Type specimens were deposited in the Insect Collection of the Department of Entomology, South China Agricultural University, Guangzhou, China.