The microchannel plate (MCP) ion barrier film produced by traditional technology affects the signal-to-noise ratio (SNR) of the image tube to a certain extent, and long-term working conditions reduce the reliability of the image tube. Due to the urgent need to improve and enhance the SNR and reliability of image tubes caused by defects in traditional ion barrier films, a new type of ion barrier film for MCP must be developed. In this study, a continuous high-quality U-shaped ion barrier film was prepared using atomic layer deposition on the inner wall of MCP channels with high aspect ratios and channel holes at the input end. The film quality and electrical performance were tested using an MCP comprehensive detection device and compared with the performance of MCP components prepared by traditional technology. The new ion barrier film is dense, with high gain values and low carbon content in the components. The new MCP components exhibit a high SNR and high lifespan reliability after tube preparation. New MCP components produced using this technology are of great significance for improving the SNR and reliability of image intensifiers.