Diachasmimorpha anshunensis sp. nov., a koinobiont endoparasitoid of larvae of Zeugodacus tau (Walker) (Tephritidae: Diptera), is discovered from Guizhou (Southwest China) and is described by multiple forms of evidence. Morphological characteristics, photographs, and molecular data differentiating it from similar species are provided. Several biological characteristics of this new parasitoid, observed in a laboratory setting, are also provided as evidence to separate it from the most similar species in appearance.