The utility model discloses a buchholz relay protection casing includes first casing and second casing, the outside at the relay is established to first casing cover, be provided with the base boss complex draw -in groove with the relay on the first casing, be provided with on the first casing and be used for the bolt hole be connected with the relay, first casing plays protect relay's effect, can shelter from solar direct projection, slow down the ages at a rate of relay, and the design of first casing also can avoid external sleet directly to drop on on the relay, can reduce the fault rate of gas transformer to a certain extent, the second casing is connected with first casing and second casing cover is established in the top of secondary line and terminal box, and the second casing can shelter from the direct projection of external sunshine, has played the effect that slows down secondary line ages at a rate, the second casing can also stop that external sleet directly drops on on the secondary line to can avoid because the sealed gas transformer trouble that does not sternly cause of terminal box.