Based on observation of vegetation quadrates of abandoned farmlands in Ansai, a loess region of hills and gullies, vegetat ion communities and their dominant species were ascertained through TWINSPAN. Results show that there are mainly 4 vegetation communities: Artemisia scoparia dominated community, Lespedeza davurica and Stip a bungeana dominated community, Artemisia gmelinii dominated community, and Bothriochloa ischaemum dominated community. The Canonical Correspondence Analysis reveals that the year since abandonment ,total phosphorus, exchangeable phosphorus and soil water content are important factors significantly effecting the variation of species in abandoned croplands. Along with the life-form characteristics, it is considered that Bothriochloa ischaemum and Lespedeza davurica have strong adaptation to site conditions, and could be the proper introducing species in abandoned croplands to accelerate and direct vegetation community succession and control soil erosion on the hilly-gullied loess plateau