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High-purity and density Sm1-2xEuxBaxB6（x=0.1, 0.2, 0.3）polycrystals were prepared by using a boron/carbonthermal reduction-hot pressing sintering (BCTR&HP) integrated process. The effect of Eu&Ba doping the SmB6 matrix on the structure, mechanical and electrical properties of Sm1-2xEuxBaxB6 bulks were investigated systematically. The results show that the Sm1-2xEuxBaxB6 polycrystals produced by BCTR&HP provide a simple cubic (CsCl type) single-phase structure. As the doping amount of Eu&Ba increased, the lattice constant increases, which contributes to the enhancement of mechanical properties and the decrease of resistivity. The thermionic emission performance results show that the Eu&Ba doping can improve the emission characteristics of SmB6 cathode, and the emission current density and zero-field current density of Sm0.4Eu0.3Ba0.3B6 cathode are 35.1 mA.cm-2 and 21.4 mA.cm-2 under the applied voltage of 1 kV at 1773 K, respectively. Meanwhile, the average effective work function is 3.6 eV from 1523 to 1773 K, and it can be used as a "direct heating" cathode benefited by its inherent high resistivity, which simplifies the heater structure and has great application prospects.