The morphological ontogeny of Neoseiulus zwoelferi (Dosse, 1957) (Acari: Phytoseiidae) was studied based on specimens from a laboratory culture originally collected from the leaves of Xanthium sibiricum Patrin ex Widder (Asteraceae) in Taigu County, Shanxi province, China. All life stages including larva, protonymph, deutonymphal female and male, adult female and male were described and illustrated. The morphological characters of Neoseiulus species with both immature and adult stages are discussed. Neoseiulus subreticulatus (Wu, 1987) is considered a junior synonym of Neoseiulus zwoelferi (Dosse, 1957).