Under the condition of multiple cropping after wheat in irrigation area of Yellow River, using Huayouza 62 as material, field experiments were conducted to study the effects of four sowing treatments on plant height, stem diameter, chlorophyll content (SPAD), fresh and dry quality of leaves, fresh and dry quality of stems, fresh grass yield and leaf area on relative productivity and net assimilation rate，including low sowing A1(7.5 kg/hm2), medium sowing A2(15.0 kg/hm2), medium sowing A3(22.5 kg/hm2), high sowing A4(30.0 kg/hm2). The results showed that low sowing rate was beneficial to the accumulation of dry matter in forage rapeseed; fresh grass yields of A2 and A3 treatments were significantly higher than that of A1 and A4 treatments; fresh and dry quality of leaf and stem of forage rapeseed treated with medium sowing rate had advantages in daily growth. Considering comprehensively, the suitable sowing rate of forage rapeseed in irrigation area of Yellow River was 15.0-22.5 kg/hm2.