北京是我国的首都、交通枢纽，有８条铁路、１６条重要公路通向全国各地。所谓“北京对外走廊”，就是指北京向外辐射的铁路线和公路线。这些铁路、公路是北京的门面，特别是京九铁路线，是北京连接香港的重要通道，相当一部分国际友人由此进京。通道两侧生态环境状况如何，直接 Beijing is China’s capital and transportation hub. There are 8 railways and 16 important highways leading to all parts of the country. The so-called “Beijing Foreign Corridor” refers to the railway lines and highway lines radiating from Beijing. These railways and highways are the facades of Beijing, especially the Beijing-Kowloon railway line. They are an important passage for Beijing to connect Hong Kong, and a considerable number of international friends have entered Beijing. How are the ecological conditions on both sides of the channel directly