An American box transformer ventilation foundation is mainly made of I-shaped channel steel. The American box transformer ventilation foundation at least comprises four pieces of channel steel connected end to end, every two pieces of channel steel are fixedly connected with each other through a piece of angle iron, and at least one piece of channel steel is provided with a ventilation hole on which a stainless steel ventilation net is installed. The American box transformer ventilation foundation is simple in structure, convenient in assembly and disassembly and applicable to all kinds of box transformers. Convection between air in a box transformer and the outside air occurs through the ventilation holes on the channel steel, which ensures that the air in the box transformer is safe and can effectively avoid the occurrence of accidents caused by accumulation of flammable and explosive gases.