The invention, which relates to the technical field of grid operation management, discloses a gateway acquisition field system checking apparatus of a transformer substation. The apparatus is composed of a portable voltmeter, a hand-held check terminal, a voltage branching wire and a charger. The portable voltmeter is connected with an RS485 port of a gateway electric energy meter arranged at a transformer substation; the hand-held check terminal is connected with the gateway electric energy meter arranged at the transformer substation; and one end of the voltage branching wire is connected with the hand-held check terminal and the other end is connected with A and B ports of an RS485 loop. According to the checking apparatus, the hand-held check terminal provides power for the checked gateway electric energy meter and thus the gateway acquisition field debugging and checking work of the transformer substation can be carried in advance before a transformer substation acceptance inspection stage, so that a defect can be discovered and eliminated before putting into operation and thus the potential safety hazard can be reduced. Meanwhile, on the basis of the structure of combination of plugging and clamping and a batch type checking way, the work hour is saved and the work efficiency is improved. Therefore, the gateway acquisition field system checking apparatus can be applied to a newly-built transformer substation acceptance inspection work.