The rocket nozzle of hybrid thruster is exposed to an extremely high-temperature environment. An ablation materials are widely used to protect thruster system by ablation cooling. However the severe ablation causes combustion pressure drop. The superior ablation resistance and refractory material are recently researched ~~. In this study, the ablation resistance of ultra high temperature ceramic(UHTC) made of HfC-SiC was evaluated including ablation analysis of existing material, graphite. The 250 N scale H2O2/High Density Polyethylene thruster was designed. The materials were exposed to highly oxidizing and high temperature rocket propulsion environment. The superior ablation resistance of HfC-SiC nozzle improved pressure drop due to the ablation and made stable propellant feeding. The abaltion of nozzles was accrately measured by 3D-scanning  and surface changesThe main research object was