Abstract: The invention refers to ferrous metallurgy, in particular, to production of grain-oriented electrical steel deployed in a manufacture of power transformer cores. Ensuring high magnetic permeability of steel and homogeneity of the magnetic properties requires slab casting, slab heating, rough and finishing hot rolling, cooling, pickling, double cold rolling with an intermediary decarburizing annealing, MgO coating application, box annealing and flattening annealing after rolling strips are cooled within the time not exceeding two seconds, the heating for the high-temperature annealing in the temperature range of 400-700° C. is carried out at the rate of 20-25° C./hour.