The invention relates to a method for preparing boron-containing high-chrome cast iron grinding balls through nanometer modification treatment and belongs to the field of abrasion resistance materials. Boron is added in high-chrome cast iron, the adding ratio of the boron is 0.2-0.4% of the weight of the high-chrome cast iron, and the high-chrome cast iron is melted into molten iron. Ferroboron isadded through the bag punching method, nanometer SiC core-spun yarn is added in a tundish according to the weight and component of the high-chrome molten iron to conduct modification treatment on thehigh-chrome molten iron, and the adding quantity of nanometer SiC is 0.03-0.08% of the weight of the high-chrome molten iron. Then the austenitizing temperature of a mixture is increased by 10-20 DEGC for complete austenitizing, quenching is conducted in biological quenching oil, and thus the boron-containing high-chrome cast iron grinding balls are obtained. According to the method for preparing the boron-containing high-chrome cast iron grinding balls through nanometer modification treatment, the technique is simple, the hardness, toughness and abrasion resistance of the finally-obtained grinding balls are all greatly improved, the using performance of the high-chrome cast iron is effectively improved, and the comprehensive using cost of ore grinding is reduced.