Abrasion mechanism of thermocouple cannula is studied in this article. For different working position and condition, different material should be selected to ensure the working characteristics of thermocouple cannula. Several protection methods were introduced to prolong the sevice life of thermocouple cannula. 1. M-Al series intermetallic compound coating protection method. 2. Metal/ceramic compound coating protection method. 3. Development of new abrasion-resisting material for high temperature according to some special work conditions of thermocouple cannula. With the adoption of those new technologies, thermocouple cannula’s service life can be prolonged to 3~5 times of that untreated.