Durable thermometric thermocouple

The utility model relates to a thermometric thermocouple with long service life, which comprises two ceramic bushings with thermocouple wire sleeves, wherein, the two ceramic bushings are welded together. The outside of the ceramic bushing of a short thermocouple is sheathed with a layered sleeve which is composed of a fiberglass belt layer and a protective paint layer. The outside of the ceramic bushing of a long thermocouple is provided with a four-layer structural sleeve which is orderly composed of a fiberglass belt layer, a stainless steel pipe layer, a fiberglass belt layer and a protective paint layer. Accordingly, the protective paint layer is made of mixing slurry which is mixed by a pyrotek coating of a flow channel, talcum powder, fireproof mud and silica gel liquid. The utility model can be used for a strong caustic working condition, and the utility model has the advantages of long service life, high measuring precision and low manufacture cost.