Abstract: The LaB₆ single crystal tip was prepared by the method of drop-off electrochemical corrosion and the technique of focus ion beam. The micro topography of LaB₆ single crystal tip was analyzed by scanning electron microscope. On this basis, the Vogel-type LaB₆ single crystal cathode is prepared. The emission performance and its application in Micro-CT are studied. The experimental results indicate that the LaB₆ single crystal cathode have higher brightness of electron beam, which can improved the X-ray intensity and the whole performance of Micro-CT.