Abstract: Since there are through-holes on the ion barrier film prepared with the normal technique, a method to measure the quality of ion barrier film is put forward to test the quantity and size of the regular or irregular apertures which cause the bright apertures on the screen by MCP electron multiplication when the low voltage is supplied to the cathode. Under the condition of assigned voltage and illumination of cathode, about 2lx light is illuminated on the photocathode, the voltage is exerted on each pole of the image intensifier to make the bright apertures on the screen to be seen distinctly, and then 10 microscope or camera is used to take pictures of the through-holes on the ion barrier film, which images on the screen. The experiment results show that under the same condition of testing, the quality of the ion barrier film is different if the craftwork of facture is different.