The invention provides an inspection device for a liquid level window of a transformer oil conservator. The inspection device comprises a holding rod, a top rod, a CCD image acquisition device and a cleaning device. One end of the top rod is fixedly disposed at a first end of the holding rod, and a second end of the top rod is provided with a pressure sensor element. The CCD image acquisition device is fixedly disposed at the first end of the holding rod, and comprises an image acquisition lens, an image display and a controller. The pressure sensor element, the image acquisition lens and the image display are all connected electrically with the controller. The cleaning device is disposed at the second end of the top rod. The technical scheme of the invention solves the problems that a liquid level display window of a transformer oil conservator is difficult to observe and clean.