We studied the effects of different irrigation and fertilization treatments on the growth of Viciavillosa Rothvar (Vetch) and the effects of the green manure on the growth of later-maize yield and soil fertility through field experiments. The results showed that both irrigation and fertilization significantly promoted the growth of Vetch. In the green manure season, irrigation could significantly increase the biomass, root activity, nitrogen and phosphorus nutrients accumulation of Vetch, whether fertilized or not. The Vetch biomass, root activity, nitrogen and phosphorus nutrients accumulation of NPW (applying nitrogen, phosphorus fertilizer and irrigation in green manure season) and CKW (no fertilization in green manure season, only irrigation treatment) consistently increased by 34.58% and 56.10%, 26.49% and 37.92%, 43.47% and 146.89%, 103.84% and 113.94%, respectively, compared with the corresponding no irrigated treatment. The amount of nutrients returned from the residual Vetch were 125.32~274.49 kg/hm², which accounted for 26.95%~59.03% of the total nutrients of chemical fertilizer in maize season. Compared with CF treatment (winter idle land treatment), the green manure growing under different fertilization and irrigation treatments promoted maize yield and nutrients accumulation and increased soil nutrients, and among the treatments, the effect of NPW treatment was the best. Under the same annual nutrient condition, 15.56% of nitrogen or 50.00% of phosphorus fertilization in the maize season transferred forward to the green manure growing season, which could significantly increase the amount of green manure nutrient returned to the field, the maize yield (8.39%~31.19%) and nutrients accumulation (7.31%~29.20%). In conclusion, under the conditions of appropriate irrigation and fertilization, the biomass of Vetch increased significantly, which had consistent increased the yield and nutrients accumulation of later-maize. The results could provide data support and practical basis for the application of green manure infield managements and fertilizer reduction in China.