To provide scientific supports for the reduction of nitrogen fertilizer during wheat production through green manure returning，the effects of nitrogen application rates on grain yield，soil fertility and economic benefits of the spring wheatsummer hairy vetch rotation system were studied in the Hetao irrigation area. A field experiment from 2018 to 2020 was carried out at the Yuanziqu experimental station of the Institute of Agriculture and Animal Husbandry Science，Bayannaoer city，Inner Mongolia. The randomized block experiment design was adopted with summer fallow without nitrogen fertilization reduction in wheat season as the control (CK)，the combination of hairy vetch returning with half aboveground biomass and nitrogen reduction in wheat season by 10% (GN90)，20% (GN80) and 30% (GN70) as treatments. Compared with CK， GN80 significantly increased the grain yield of spring wheat by 12% in 2019，and GN90 and GN80 increased by 16% and 13% in 2020，respectively. Nitrogen reduction in spring wheat season had no effects on the fresh grass yield of summer hairy vetch，and the yield of hairy vetch in 2020 was only 52% of that in 2019. Combined with the 10%-30% reduction of nitrogen fertilizer in wheat season，the multiple cropping of summer hairy vetch significantly increased the number of spikelets and 1000-grain weight of spring wheat，thus achieving higher grain yield. Compared with CK，the multiple cropping of summer hairy vetch had no effect on soil total and available nutrient contents in 2019，while remarkable increases were found in 2020. GN90 increased soil organic matter by 37%. GN90，GN80 and GN70 increased soil total nitrogen by 40%，23% and 17%， respectively. GN90，GN80 treatments increased available phosphorus by 21%，23%，respectively. In 2019，the economic benefits of GN90，GN80 and GN70 were increased by 39%，33% and 29%，respectively，compared with CK. In 2020，the net income of GN80 and GN70 were 3% and 5% lower than CK，respectively，due to the sharp decrease in the production of hairy vetch forage. Overall，the multiple cropping of summer hairy vetch and half returning，combined with nitrogen reduction by 10% in the subsequent wheat could increase wheat grain yield，improve soil fertility，and increase economic and ecological benefits. It could be a green and efficient farming system for spring wheat planting in the Hetao irrigation area.