In Gansu Hexi oasis irrigation area，experiment was carried out to study the effect of longterm application of green manure and reduced fertilizer on multiple cropping Vicia Villosa Roth yield and soil fertility.The results showed that with application of green manure and fertilizer reduction，multiple cropping Vicia Villosa Roth produced 17 093~19 110 kg/hm2 green manure.Compared with those of the farmers fertilization practice，for treatment of reduced 30% of fertilizer the output value increased by 12 091 yuan/hm2，the economic benefit improved by 64.7%，soil organic matter increased by 1.8 g/kg，soil alkaline hydrolysis N increased by 10.5 mg/kg.High N application amount was not good for the accumulation of soil organic matter.Application of green manure 7 500 kg/hm2 could replace 67.5～90 kg/hm2 N fertilizer，and could improve soil fertility，save energy，reduce emission and have synergy effect.