The invention discloses a master-slave upper port protective switching method and device based on a UTN tunnel. Master-slave protection is conducted on a UTN device core exchange unit through an FPGA,the BFD states of master-slave circuits are detected in the FPGA and interacted, a master-slave service switching instruction is transmitted, and rapid and stable carrier-class protection is realized. The link state between systems can be rapidly and stably detected, the BFD states of the systems are synchronized, and it is ensured that the master-slave port switching is completed within 35 ms.