Aiming at the problem of Tungsten-Rhenium thermocouple tracing at a temperature of 300 to 1500 ℃, the prior horizontal-type calibration furnace is improved. It adopts a symmetric shielding gas method for calibration and adds a set of temperature-resistant cavity seal kit which can vacuumize and fill in inert gas to prevent thermocouple being oxygenized. The test shows that the device has good consistency in calibrating the same thermocouple under the vacuum and charging state; and this device can make calibration for extension-type tungsten-rhenium thermocouple with outer diameter betweenφ3～φ10 and length over 450mm.