Abstract: To meet the requirement of radiation heat flux measurement on aerodynamic configurations mounted in hypervelocity and short duration flows in high enthalpy impulse wind tunnels, a transient radiation heat flux sensor was developed. The radiation heat flux sensor was designed based on thin-film sensor, where a radiation absorption layer was fabricated on the thin-film and a radiation transmittable window was added in front of the sensor to insulate the convective heating. The radiation heat flux sensors were tested in laser beams and shock tube flows to examine the response characterisctics, and were tested for radiation heat flux measure-ment at the stagnation point of a re-entry capsule in a hypervelocity flow with the velocity of 11 km/s generated by the High Enthalpy Expansion Tunnel. Experimental results prove the fast response ability of the sensors and showed resonable agreement of measured radiation heat flux with predicted values, verifying the feasibility of the sensor for radiation heat flux measurement in high enthalpy pulse wind tunnels.