The invention belongs to the technical field of computers, and relates to a one-computer double-network physical isolation computer, in particular to a double-host satellite positioning security computer with a multi-channel switching circuit. The computer comprises a master control system, hosts, a power source and a machine case, wherein the master control system comprises an intelligent master control unit and a switching unit. The two hosts include the host 1 and the host 2 respectively, physical shielding isolation is achieved between the two hosts, connectors of a keyword and a mouse of the host 1 and connectors of a keyboard and a mouse of the host 2 are respectively connected to the multi-channel switching unit of the intelligent master control system, and the double hosts are switched for use through the intelligent master control system. The computer can be used for integrated desk computer industrial production, has the triple illegal starting preventing function, the one-way information conversion function, the outage preventing active protection function, the active or passive self-destruction function and the like, has good application prospects in the technical field of computers, and makes contributions to departments such as party and government organizations, army, national defense, scientific research institutions and enterprises.