With the development of the information age, video transmission systems have been widely used. Video transmission systems are widely used in daily life, especially in large conferences, government systems, and military command systems. At the same time, for video transmission systems The attack methods of the video transmission system are also gradually developed, which poses a huge threat to the information security of the video transmission system. Combining with the composition of the video transmission system, the paper analyzes the security threats of the video transmission system from the preset backdoor attack of the video transmission system, electromagnetic leakage attack, power line carrier attack and transmission line attack, and aims at the current command hall and other needs to have multiple security levels. A protection scheme is put forward for the situation that the equipment is connected to the same large screen for display at the same time, which provides a reference for the design and protection of the future video transmission system.