The effects of long-term application of different green manure on soil fertility and maize yield were discussed，so as to provide reference for seed selection of green manure in southwest China.Based on a 7-year long-term fixed-position experiment，three varieties of green manure were selected and four treatments were set up，including no green manure+conventional fertilization(CK)，Osmunda glabra+conventional fertilization(CV)，radish+conventional fertilization(CR)and ryegrass+conventional fertilization(CL)，and the differences of maize yield，maize nutrient absorption and soil nutrient content with different green manure were analyzed and compared.Under different green manure treatments，the average yield in the six years from 2018 to 2023 showed as CV>CR>CL>CK，with significant differences among the treatments.Compared with CK，the average nitrogen and phosphorus content in CV treatment and the average potassium content in CL treatment of maize grain treated with different green manure were the highest in two years.The average nitrogen content of straw in CV treatment was increased by about 36.5% compared with CK，the average phosphorus content of straw in CL treatment was increased by about 75% compared with CK，and the average potassium content of straw in CV treatment was significantly higher than other treatments.From the average value in 2019 and 2023，CV，CR and CL treatments all increased the nitrogen and potassium content of maize grain and the nitrogen，phosphorus and potassium content of straw to varying degrees.Compared with CK，the average grain nitrogen absorption and potassium absorption increased by 1.3%-20.0% and 5.2%-47.9%，respectively，the grain nitrogen absorption efficiency increased by 1.5%-20.4% and the two-year average potassium absorption efficiency increased by 5.0%-52.9%.The average values of maize grain absorption and absorption efficiency ranked as CV>CL>CR>CK.On the whole，different green manure treatments could improve the soil nutrient content，among which Osmunda glabra had the most obvious effect on improving total nitrogen and alkali-hydrolyzable nitrogen contents，and radish and ryegrass could improve the soil phosphorus and potassium content to varying degrees.Therefore，in the selection and planting of green manure in southwest China，the planting of Osmunda glabra could maintain and improve corn yield，improve soil productivity，promote the absorption of nitrogen，phosphorus and potassium nutrients in maize grain and straw，and improve soil fertility.