The external and internal structures of male and female adults of Culicoides grisescens Edwards, were examined with scanning electron microscope (SEM) and tissue section techniques. Specimens were collected from Qilian Mountain National Park in Qinghai Province, China. The ultrastructure and morphology of compound eyes, antenna, maxillary palpus, spermathecae, genitalia and other structural characteristics of both male and female adults of C. grisescens are described. Internal structures of the species are described, including histological sections of the digestive, nervous, respiratory, and reproductive systems. This paper provides visual and descriptive details for the systematic taxonomic study of Ceratopogonidae.