The invention relates to a cathode ring antireflection film for OLED micro-display and a preparation method thereof. The preparation method comprises the following steps: preparing a cathode layer of an OLED micro-display with a cathode ring; then loading the cathode ring antireflection layer mask onto the cathode layer of the OLED micro-display; using a mask coating method and through the cathode ring antireflection layer mask, depositing the anti-reflection material on the cathode layer of the OLED micro-display to make a layer of anti-reflection film. This can quickly and easily solve the problem of bright edges in the periphery of the display area of the display. The method not only does not affect the optoelectronic performance of the device, but also has high process matching, good shielding effect and high process compatibility. The cathode ring anti-reflection film for the OLED micro-display prepared through the method can completely block a display area, thereby greatly reducing the damage to the device caused by magnetron-sputtering high-energy particles.