The invention discloses a converter transformer provided with a glass tube type oil-level indicator. The converter transformer comprises a converter transformer body, wherein the top of the converter transformer is communicated with an oil conservator; an air bag is arranged in the oil conservator; the top of the air bag is communicated with one end of an air tube; the other end of the air tube is communicated with one end of a respirator; the other end of the respirator is inserted into a respirator oil cup; the bottom of the converter transformer body is communicated with an oil tube; the oil tube is communicated with a transparent glass tube; a floating ball is arranged in the transparent glass tube; the upper end of the transparent glass tube is communicated with the air tube through an exhaust tube; and a scale line is arranged on the transparent glass tube. A mounting method of the glass tube type oil-level indicator comprises the following steps: emptying the transformer oil in the oil conservator; forming mounting holes in the bottom of the converter transformer body and the air tube respectively; welding the oil tube on one mounting hole, and welding the exhaust tube on the other mounting hole; mounting the transparent glass tube between the oil tube and the exhaust tube, and mounting the floating ball in the transparent glass tube; setting a scale line on the transparent glass tube; opening an oil outlet valve and the exhaust tube. The invention is suitable for the converter transformer.