A wafer and DUT inspection apparatus and a wafer and DUT inspection method using thereof are provided. The apparatus includes a vacuum chamber, a stage, an electron gun, a lens system, an optical mirror and a detector. In the vacuum chamber, the stage is disposed near a first end, and the electron gun is disposed near a second end opposite to the first end. The lens system disposed between the stage and the electron gun is a total reflective achromatic lens system including a first lens and a second lens. The second lens having a second aperture is disposed between the electron gun and the first lens having a first aperture aligned with the second aperture. The optical mirror is disposed between the lens system and the electron gun. The detector is horizontally aligned with the optical mirror and configured to detect cathodoluminescence reflected from the optical mirror.