In order to better realize and ensure the security performance of network information itself, various possible risks must be prevented in advance, and a more reliable operation environment must be created as much as possible. A research study on computer video information encryption and antileakage technology based on the digital information method is proposed. Through the research on the working principle of computer display systems, this paper analyzes the common leakage sources. On this basis, it analyzes how to protect the electromagnetic wave leaked from the computer display system. Finally, it is proposed that the protective measure adopted in this paper is (transient electronic pulse emission survey technology, tempest) technology; that is, the image is processed at the source of image information to reduce the electromagnetic radiation of useful information. The corresponding digital filter is designed by fir, and the combined filtering of digital filter and analog filter is applied to eliminate the inherent disadvantage of periodic fluctuation of insertion loss of the digital filter. The research results show that the receiver before filtering can receive video images at multiple frequency points such as 20 MHz, 160 MHz, 220 MHz, 250 MHz, 270 MHz, 290 MHz, and 340 MHz, while the receiver after filtering can only receive video images at two frequency points of 20 MHz and 250 MHz, but it cannot recognize the words in the figure, and its effect is very obvious. It verifies the correctness and effectiveness of the theoretical analysis in this paper.