Abstract: In order to solve the problem that sensitive data of all kinds of railway Beidou terminal measurement devices may be stolen and tampered in the process of data transmission, this paper studied the application technology of security protection for railway Beidou data. Relying on the railway Beidou application service platform, and combining with the application of password chip protection technology, the paper designed the Beidou data password security protection system to transmit the encrypted sensitive data, so as to ensure the confidentiality, integrity, availability and authentication of the relevant application data, which was of great significance to the practical application of Beidou technology in the railway industry.