The utility model discloses a device for testing aging of oriented silicon steel in an oil bath for a transformer. The device comprises an oil storage tank, an oil pump, an oil conservator, an oil level meter, an oil conservator valve, a bracket of the oil conservator, a deflation valve, a deflation hole and a breather, and is characterized in that the oil conservator is connected with a test oil bath box through a gas guide pipe; a thermocouple wire outlet pipe, a temperature inspector, a vacuum pump, a vacuumizing valve, a thermal balance circulating pump, an oil sample valve and an oil injection and drainage valve are respectively arranged on the test oil bath box; the device further comprises a supporting plate connected into the test oil bath box, a heating cavity formed by the supporting plate and the bottom end of the oil bath box, an electric heater and a PID temperature controller which are arranged in the heating cavity, an oil guide hole and a positioning block which are arranged on the supporting plate, an oil channel cushion block on the supporting plate, a test sample bracket on the oil channel cushion block, a thermocouple connected with the test sample bracket, and a test sample fetch hole and a cover plate which are arranged on the top of the test oil bath box; the thermocouple is connected with the thermocouple wire outlet pipe and is sealed by epoxy resin. The device can be used for simulating an inner environment during running of the transformer, providing a reliable basis for research on the oriented silicon steel and meeting a demand of market.