The invention discloses a protocol security isolation system oriented to a railway signal control network. The protocol security isolation system is composed of a first communication interface 101, a second communication interface 203, a first processor 102, a second processor 202, a high-speed dual-port RAM communication buffer memory 302, a memory RAM, a power-failure memory FLASH, a human-computer interaction platform 105 and a power module 301. The first communication interface and the second communication interface intercept and capture data, corresponding the network, from a link layer, the data are sent to the first processer to be analyzed, an analysis result and communication content are sent to the human-computer interaction platform 105 to be displayed and are written into a data base, safe network data information is sent to the second processor through the high-speed dual-port RAM communication buffer memory 302 in a ferry mode at the same time, and the safe network information is sent to a target terminal or a target network through the second communication interface 203 driven by the second processor. According to the protocol security isolation system oriented to the railway signal control network, multiple network technologies are combined and real-time monitoring and security isolation are carried out on the existing railway signal control network.