In order to ensure national security and protect state secrets, it is necessary to obtain the corresponding pass to enter Yushan Island. This is to control people entering the island, prevent unauthorized people from entering the military restricted zone, and ensure national security and the confidentiality of military secrets. According to the Law of People's Republic of China (PRC) on Guarding State Secrets, the secret matters in national defense construction and activities of the armed forces are state secrets, which may damage the security and interests of the country in the political, economic, national defense and diplomatic fields.