A high-enthalpy plasma facility with 0.4 MW power level has been constructed at Chonbuk National University in Korea. A segmented arc plasma torch was adopted as a plasma source for this facility. It is designed to have high thermal efficiency and long life in the production of supersonic plasma flow with enthalpy above 13 MJ/kg at a velocity of Mach 3. Diagnostic systems include enthalpy probe with mass spectrometer for the measurement of enthalpy, plasma composition and plasma temperatures, and heat flux probe for the measurement of heat flux. Visualization systems such as a pyrometer, a fast camera and an emission spectroscopy have been installed to monitor the surface temperature of the substrate, the plasma density and flow patterns.