Abstract: With the continuous development of railway informatization, railway enterprises have established their own electronic document systems for internal document approval and circulation. However, there is still a lack of secure and effective ways and means of document exchange between railway enterprises and between superior and subordinate enterprises. This paper designed a railway electronic document exchange system based on digital envelope encryption transmission technology, and elaborated on system architecture, system functions, and key technologies. The trial shows that the application of this system can effectively improve the efficiency of document exchange between railway enterprises, reduce the risk of information leakage, and has certain promotional value.