The invention provides a transformer oil level check device and method. The transformer oil level check device comprises a first oil chamber, a first solenoid valve, a second solenoid valve, a pressure sensor, a heater and a controller, wherein the first solenoid valve is arranged at a first oil inlet-outlet, the second solenoid valve is arranged at a second oil inlet-outlet, the heater is arranged in the first oil chamber and is connected with the controller and is used for heating an oil liquid placed in the first oil chamber to a preset temperature, the pressure sensor is arranged on an a bottom surface of the first oil chamber, is connected with the controller and is used for acquiring pressure information applied to the bottom surface of the first oil chamber and sending the pressureinformation to the controller, and the controller is used for calculating an oil level height value in an oil conservator of a transformer according to the pressure information, so that a worker can complete check operation on ground, and a potential risk is eliminated.