The Ba-W cathode consists of the porous W matrix and the aluminate. During cathode operation, the Ba atoms are generated in the pores by the thermal reaction between the W and aluminate, and then diffuse along the pores channels to the W surface to lower the work function. Therefore, the Ba yield and the Ba diffusion are significantly influenced by the micro pore structure of the matrix and the phase composition of the aluminate. Firstly, the matrix is fabricated with the narrow particle size distribution powder by spark plasma sintering (SPS) technique, which shows the narrow pore size distribution (FWHM=0.43 μm). Then the spherical powder with good fluidity and high tap density is prepared using RF induction thermal plasma. The matrix prepared with spherical powder exhibits narrower pore size distribution (FWHM=0.4 μm), smooth pore channels and good inter-pore connectivity. The two matrixes prepared with narrow particle powder and spherical powder are named N-matrix and S-matrix, respectively. The aluminates are prepared using the solid phase method and the liquid phase method, respectively. The particles of solid phase aluminate precursor come in all shapes and all sizes, while the particles of the liquid phase aluminate precursor are uniform in size and same in shape. The phases of the solid phase aluminate and liquid phase aluminate are analyzed by XRD, the results show the former consists of the effective Ba3CaAl2O7 phase and other impurity phases, while the latter consists of two effective phases of Ba3CaAl2O7 and Ba5CaAl4O12. The N+S and S+S cathodes are obtained by impregnating the N-matrix and the S-matrix with Solid phase aluminate, and the U-j characteristics of the two cathodes are investigated. On the double logarithmic curves of U and j, the slope of 1.37 in the space charges limited (SCL) region for the S+S cathode is higher than that of 1.25 for the N+S cathode, so the S+S cathode exhibits better emission uniformity. The current densities at the deviation point (jDEV) of the N+S and S+S cathodes are 6.6 A·cm-2 and 6.96 A·cm-2. So the improvement on the matrix obviously raises the emission uniformity of cathode, but the current density is raised few. Based on the excellent matrix of the S+S cathode, the S+L cathode is obtained by improving the aluminate of the S+S cathode with Liquid phase aluminate. The U-j characteristics shows the slope of the S+L cathode reaches to 1.44, and the jDEV is 21.2 A·cm-2. So the improvement on the aluminate not only increases the uniformity, but also raises the current density. The study shows that the U-j curve calculated by the classical thermionic emission (TE) theory agrees well with that of the S+L cathode at 1000 ℃, which indicates that Ba-W cathode follow the classical TE theory rather than other emission theories, and Ba-O dipole layer just changes the work function of the cathode.