Abstract: The paper reports one new species and one new record of genus Topomyia collected from bamboo holes in Xishuanbanna of Yunnan.This new species is similar to To.yanbareroides and To.spathalirostris.But this new species distimere of male expanded like drum-hammer at apex,and with some small hooked hair;its larvae,seta 5-c of head outer of 4-c,maxillae with a tuft of hair at apex.These characters are very easy to distinguish from others species.Type species:holotype,1 male;allotype,1 female;paratypes,1 male,1 female,4 larva akines,4 pupa akines,all collected from bamboo holes in Jinhong of Yunnan Province,Ⅸ 1995 by Dong.All the types are deposited in the Institute of Malaria Prevention and Treatment of Yunnan Province.