La-Y-Ce-W cathode was prepared by powder metallurgy. XRD, OM, SEM and EDS were applied to analyze the microstructure of the material. La, Ce and Y concentrate on the tungstate particles and exist as Rare Earth (RE) tungstate. The average diameter of the particles is about 30µm. The electron emission properties were measured with self-designed electron emitter surveyor. Its effective work function was 2.76eV at 1300°C. The precipitation efficiency of an electrostatic precipitator (ESP) installed with the cathode was investigated in a certain flue gas condition. It was found that it can trap over 95% dust particles with diameter bigger than 1µm. As to dust particles with diameter smaller than 0.1µm, the efficiency is lower than 85%. Increasing collection voltages showed greater positive effects on the precipitation efficiency of smaller particles than that of larger particles.