The invention discloses a restoration method for a seriously deteriorated grassland of a subalpine mountain in western Sichuan. The restoration method includes the steps that in the period of soil freezing, the range of the grassland needing to be restored is determined; the determined restoration range is divided into first blocks and second blocks with meshes, and the second blocks are regions for planned fire utilization; a fireproof strip is cut on the boundary of each second block, and a fireproofing facility is installed on the fireproof strip; the lower point of a slope is ignited so that dry grass in the second blocks can be burned naturally; after planned fire utilization is implemented, cow dung mixed with grass seeds is spread on the surface of the burning regions; after first rain in the regions, the fireproofing facilities are disassembled. While biodiversity of the grassland is ensured, productivity on the ground part of the whole grassland ecological system is restored, and more biological resources are provided for the summer grassland and winter grassland in the regions. Normal grazing utilization is carried out according to a grass and livestock balance system, the whole restoration cycle is short, it can be effectively avoided that soil conditions tend to deteriorate, and the restoration method has a positive effect on preventing land desertization.