The invention relates to a method for planting high-quality forage grass in meadow grassland by applying a no-tillage method. A targeted repair scheme is designed according to different degradation degrees of the meadow grassland, and the problem that the soil nutrients are insufficient is solved by applying a soil conditioner. A high-efficiency root cutting device capable of cutting roots along aplurality of directions is researched and developed according to a soil hardening problem caused by perennial growth of perennial gramineous plants. The invention provides the improvement method, wherein the current situation of the meadow grassland is comprehensively considered, restriction factors of plant growth are reduced or relieved, the cost is low, and the effect is remarkable, so that ecological restoration of the meadow grassland is achieved, and sustainable and healthy development of animal husbandry of the grassland is maintained.