Abstract: Given that the existing Loran-C transmission reference monitoring system suffers from instability and tends to malfunction under severe weather conditions and complex electromagnetic environments, this paper proposes a transmission reference monitoring method based on network time synchronization. The time information of the proposed method is obtained from the wired internal network, while the measurement signals are generated by the second pulse signal of the atomic clock timekeeping system synchronized via common-view equipment and the group trigger pulse (GTP) signal of the transmitter. Transmission reference monitoring is realized through a combination of real-time measurement and data calculation. Corresponding upper computer software is also developed to support the monitoring work. Adopting wired channel data and local station timekeeping signals, this method boasts high stability and strong anti-interference performance, which substantially enhances the safety and reliability of transmission reference monitoring for ground stations.