The invention is applicable to the nuclear power station aseismic field and provides an aseismic structure for a commutation device of an emergency power system of a nuclear power station. By arranging channel steel and reinforcing steel beams, the structural strength of a machine cabinet and the aseismic performance are improved to bear high-intensity earthquakes, so that the machine cabinet cannot be deformed to guarantee devices such as a power supply and an instrument control device to operate normally in the earthquakes, further the security operation of the nuclear power station can be guaranteed; and by arranging densely-distributed mounting through holes on the channel steel, the mounting positions of related parts can be adjusted conveniently according to actual situations, so that the product versatility is good and the application cost is low.