Abstract: The friction and wear behaviors of two type hot-work die steel were studied at high temperature on the UMT-S teat system. The morphology features and phase of worn surface and subsurface were analyzed by scanning electron microscope and X-ray diffractometer. The results show the SDCM-SS steel presented higher wear resistance than H13 steel at high temperature. The wear rate and friction coefficient of SDCM-SS steel was less than H13 steel under the same condition at elevated temperature. Mild oxidative wear was the dominated wear mechanism for SDCM-SS steel at 400 ℃ to 700 ℃. However, mild oxidative wear was the dominated wear mechanism for H13 steel at 400 and 500 ℃; severe oxidation wear was the mainly wear mechanism for H13 steel at temperatures up to 600 and 700 ℃. The high oxidation resistance and temper stability rendered SDCM-SS steel wider temperature range of mild oxidative wear as well as higher wear resistance than that of H13 steel. A carbides layer at the boundary of matrix and tribo-oxide layer was due to the aggregation of carbides during sliding. This carbides layer was beneficial to the high temperature wear resistance of hot working die steel.