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To improve the Y-Gd-Hf-O pressed cathode thermionic emission ability, Sc2O3 doped different molar ration of Y2O3/HfO2 pressed cathodes are prepared. The cathode with ratio of 5/2 demonstrates the best emission ability of 2.79 A/cm2 at 1500℃. The cathode has worked stably over 1320 h at 1500 ℃ with the load of 1 A/cm2 during the lifetime test, and the emission decrease to 86% of the initial one under 10 W, 696 h continuous bombardment at the same temperature, reflecting a good anti-electron bombardment ability. XPS depth profile results show the main active substances in work are concentrated in the depth range of 50 nm from the surface. After cathode being activated, the SEM and EDS results show the active materials diameter increase to an extent, and the surface n-type semiconductor contents increase with the Y2O3, which is favorable for enhancing the conductivity, improving thermionic emission, and lowering the work function.