Silicon carbide thermocouple protection tube is formed and sintered at high temperature by extrusion process. The outer diameter of the pipe is monitored online with a laser caliper, and the pipe wall is uniform, the surface is smooth, the roundness is good, and the straightness is good. The outer diameter of both ends of the pipe can also be partially polished according to the special needs of customers. In the temperature measurement field, as the requirements become higher and higher, such as working conditions with high temperature differences, we have developed a protective sleeve made of high-purity silicon carbide material. They are porous material recrystallized silicon carbide (HALSIC-R) and impermeable material reactive sintered silicon carbide (HALSIC-I) and pressureless sintered carbonized (HALSIC-S). Due to their excellent properties, our thermocouples Protective tubes provide longer life even in demanding applications..