Ion barrier film is an important part of the third generation low-level-light image intensifier, and its quality plays an crucial role in lifetime and field of view of image intensifier. The effect of ion barrier film quality on the field of view of image intensifier was studied. The ion barrier micro-channel plate (MCP) with typical defects was selected to analyze the field of view of ion barrier MCP at runtime and the quality of ion barrier film, and the effect of ion barrier film defects on field of view of image intensifier at runtime was obtained. The reason for the defects generated in the preparation process of ion barrier film was analyzed, and the solutions to defects were preliminarily put forward, which had a very positive effect on the subsequent preparation of high-quality ion barrier film.