The invention discloses a connection device for a silicone respirator and a breathing tube of a transformer, and a silicone replacement method of the connection device. The connection device comprises the silicone respirator, the breathing tube and an interlayer, wherein the silicone respirator comprises a glass container filled with silicone inside, a first flange is fixedly arranged at an end opening of the glass container, and a second flange is fixedly arranged at an end opening of the breathing tube; a through hole is formed in the middle of the interlayer, the interlayer is fixedly connected with the second flange, and the through hole is communicated with the breathing tube; first hook locks and second hook locks which are rotatable are connected with the peripheral wall of the first flange, lugs and locking screws are arranged on the peripheral wall of the interlayer, and the first flange and the interlayer are connected in a sealed, fixed and abutting manner by hooking the first hook locks on the lugs and hooking the second hook locks on the locking screws; the end opening of the glass container is communicated with the through hole, and the second hook locks are fastened or loosened by screwing in or screwing out of the locking screws. The connection device has the advantages as follows: mounting and dismounting are convenient and quick, and time and effort are saved.