The invention relates to a method for grinding materials in a rotating drum by ferromagnetic grinding bodies and can be used in the processes of the preparation of raw material for beneficiation, as well as in construction, chemical and others industries. The essence of the invention is that the grinding of the materials is carried out in a rotating drum, partially filled with ferromagnetic grinding bodies, wherein the grinding bodies are affected by the magnetic force of at least one electromagnet, mounted on the drum, and the magnetic field is formed by separate pulses in the quantity of not less than two, wherein the first pulse is divided into a number of shorter pulses. In contrast to the prototype, the first pulse is characterized by alternating-sign magnetic field, it is fed at an angular position of the electromagnet from -60° to -30°, where the central angle begins from a vector directed from the axis of rotation of the housing vertically downwards, the second pulse is characterized by constant magnetic field, it is fed at an angular position of the electromagnet from 0° to +30°, and its feeding is stopped at an angular position of the electromagnet from 110° to 165°. The technical result is the improvement of the energy efficiency of the process of grinding materials in ball mills.