The protection of key information infrastructure has become the core of the cybersecurity legal system in most countries. The institutional design of this protection system in the US and some other foreign countries includes the following five aspects：construction of a mechanism for collaboration between the government and industries；formulation of a national-level protection plan；establishment of information sharing and analysis centers；assessment of vulnerability risks and determination of priority protection measures；and adoption of a cybersecurity framework. By drawing on the relevant foreign experiences，the author of this report puts forward the following suggestions on the implementation of the key information infrastructure protection system in China：firstly，to define key information infrastructure from the height of national security；secondly，to further rectify the system of leadership over key information infrastructure protection；thirdly，to appropriately deal with the relationship between the protection of key information infrastructure and the graded cybersecurity protection；fourthly，to further elaborate the special obligation of key information infrastructure protection；and fifthly，to attach equal importance to security and development in the construction of a collaboration mechanism between the government and enterprises.