Abstract: 【Objective】 To explore the effects of mixed sowing of different green manure varieties on nitrogen, phosphorus and potassium nutrient retention and emission reduction in double cropping rice areas in southern China during winter fallow period, so as to provide reference basis for effectively reducing the loss of nutrients in paddy fields during the winter fallow period and improving the agricultural ecological environment.【Method】From 2019 to 2020, a plot experiment was conducted to design 8 treatments of single or mixed sowing of common green manure, such as Astragalus sinicus L.,Brassica napus L.,Lolium perenne L. and Raphanus sativus L. in the fertile field,with natural grass as blank control,to monitor the loss of nitrogen, phosphorus and potassium nutrients in water, and to detect the total biomass of green manure, total carbon, nitrogen, phosphorus and potassium contents of plants and the corresponding nutrient contents in soil during winter fallow period in double cropping rice area.【Result】The overall effect of nitrogen, phosphorus and potassium nutrient retention and emission reduction in paddy field with green manure treatment was better than that of the control treatment(natural grass). The loss of total nitrogen, phosphorus and potassium contents in the treatment of planting green manure decreased by 27.7%-47.6%, 14.3%-65.5% and 9.8%-93.6% respectively compared with the control treatment. The total nutrient loss of L. perenne treatments was significantly lower than that of other treatments(P<0.05, the same below). Compared with the control, the total biomass in the treatment of planting green manure increased by 46.9%-378.7%,the contents of total carbon, nitrogen, phosphorus and potassium contents in the treatment of planting green manure increased by 67.9%-377.1%, 55.4%-2613.6%, 68.0%-557.8% and 100.0%-664.5% respectively. The total nutrient retention of A. sinicus treatments was significantly higher than that of other treatments. Compared with control,the contents of soil active organic matter, slow-release potassium and cation exchange capacity in the treatment of planting green manure increased by 21.3%-29.8%, 1.6%-5.7% and 1.3%-8.2% respectively, and the contents of soil available phosphorus and available potassium decreased by 2.3%-17.0% and 3.7%-30.1% respectively.【Conclusion】 Planting green manure in double cropping rice areas in southern China during winter fallow period has a significant effect on nutrient retention and emission reduction in the field. The mixed planting of A. sinicus and L. perenne(A. sinicus:L. perenne=4:6)has the best effect on reducing the loss of total phosphorus and potassium in water and improving the retention of total carbon, phosphorus and potassium in plants.