Plasma-sprayed scandia-doped oxide cathode is prepared by doping a small amount of scandia into the triple carbonates and employing the air plasma spraying technique. In the preparation process, a small amount of scandia is added in the shaping process of mixing the triple carbonates with an additional 12%22% of BaCO3 (molar ratio). The shape and the distribution of the feed material analyzed by using scanning electron microscope show that the size and the shape of the feed material meet the requirement for plasma-spraying and that it fully compensates the loss of barium in the plasma-spraying process. The analysis of the decomposition process shows that scandia-doped plasma-sprayed oxide cathode has a shorter process of decomposition and less exhausted gas amount than the commonly-used oxide cathode. The test on the emission performance of the new type oxide cathode shows that the emission performance of scandia-doped plasma-sprayed oxide cathode is much better than that of commonly-used oxide cathode and that the life time of the former is longer than that of the latter.