［Objective］To meet the integrity, confidentiality and availability requirements for inter-network video transmission of different security levels in urban rail transit system, it is necessary to develop a secure and reliable one-way video transmission scheme that ensures video data flows only from low security networks to high security networks.［Method］A one-way video transmission scheme based on two endpoint devices is proposed. The overall architecture of the scheme is introduced, and a proprietary Ethernet-based protocol is designed. UPET (unidirectional private exchange tunnel) technology is employed for the design of one-way transmission channels, and FEC (forward error correction) technology is used for error correction and verification design. Based on these, the data transmission process of the proposed scheme is established. Relevant software and hardware are integrated to validate the testing effectiveness of the proposed scheme, and the actual performance of the scheme is evaluated over a one-month operational period on multiple urban rail transit lines in Shanghai.［Result & Conclusion］Compared with conventional UDP (user datagram protocol) transmission methods, the proposed one-way video transmission scheme demonstrates more stable data transfer rates and lower latency, meeting the real-time transmission requirements of urban rail transit services. The proprietary protocol design in the proposed scheme effectively avoids the vulnerabilities associated with general-purpose protocols and enhances resistance to network attacks, thereby ensuring synchronous video transmission across classified networks.