The utility model discloses a bell type lower oil tank and transformer body positioning system of an oil-immersed transformer. The bell type lower oil tank and device body positioning system comprises a transformer body 1 and a lower oil tank 4 and is characterized in that a conical laminated wood cushion block 6 is fixedly arranged around a lower iron-core clamping piece 5 of the transformer body 1. The laminated wood cushion block with certain taper is fixedly arranged around the lower iron-core clamping piece; therefore, when the transformer body sinks to the bottom of the tank, the laminated wood compacts the surrounding tank edge according to a set taper; when the transformer is filled with oil, the laminated wood reversely compacts the tank edge of the lower oil tank through an expansion property, so that the oil used on the transformer is saved.