Abstract: In order to find the best basal fertilizer ratio in planting ryegrass in paddy soil in southern China, a field experiment was conducted to study the effect of different fertilizer rates on the biomass yield and the N, P, K absorption of annual ryegrass. Four levels and 11 treatments were set for the fertilization of nitrogen, phosphorus and potassium fertilizer. The biomass yield of ryegrass was estimated. The nitrogen, phosphorus and potassium content of ryegrass were tested and analyzed, and the N, P and K absorption of ryegrass were calculated. It showed that when planting ryegrass in paddy soils derived from granite, fertilization, especially nitrogen fertilizer, increased the height and biomass yield of ryegrass. Application of phosphate fertilizer as basal fertilizer and nitrogen fertilizer as top dressing fertilizer improved the regeneration of ryegrass. With the increase of nitrogen and phosphate fertilizer rates, the nitrogen and phosphorus content of ryegrass were also on the rise. After a certain amount of potash application, the potassium content of ryegrass did not change much with further potash application. Nitrogen, phosphorus and potassium fertilizer could all increase the N, P and K absorption of ryegrass. As for the basal fertilizer, the recommendation fertilization rates on ryegrass were given as N 210.0 kg/hm², P₂O₅ 108.0 kg/hm², K₂O 117.5 kg/hm², respectively, when planting ryegrass in paddy soils derived from granite in southern China.