The invention relates to an oil level visible type capacitive voltage transformer comprising a metal expander, a capacitor voltage divider and an electromagnetic unit. The metal expander is installedat the upper end of the capacitor voltage divider; and the inside of the metal expander is communicated with the inside of the capacitor voltage divider. The metal expander includes an oil injection valve, an expansion box, an oil level gauge, a corrugated oil guide pipe and an outer cover; and an oil level observation window is arranged at the position corresponding to the oil level gauge at theouter cover. The transformer is designed reasonably. The metal expander is externally installed and is provided with the oil level gauge and the observation window, so that the situation of the insulating oil in the voltage divider of the capacitive voltage transformer can be obtained visually and the real-time observation of the oil level of the capacitive voltage transformer is realized; and thus the hidden danger of internal oil shortage is discovered timely and fault occurrence is avoided, so that the safety and reliability of grid operation are improved.