A UHV main transformer respirator silica gel replacement special tool comprises a cart, wherein the upper part of the cart is connected with a counterweight and a fixed plate; the upper part of the fixed plate is equipped with a sliding rod; both ends of the sliding rod are connected with the fixed plate; and the middle part of the sliding rod is sleeved with sliding tubes that can slide on the sliding rod. The respirator replacement tool can slide horizontally through the combination of the sliding rod and a handle, so as to protrude from a side of the cart. Thus, when a flange obstacle is present, the respirator replacement tool can extend directly under the transformer respirator so as to conveniently replace the transformer ventilator.