Abstract: The construction of cloud platform is significant to enhance the informationization level of the urban rail transit and to push forward the development of smart urban rail transit. Through analyzing the problems and challenges encountered, it is proposed that emerging cloud computing technology should be used to tackle such problems as insufficient data sharing, low utilization rate of equipment resources and complicated operation and maintenance of information systems. Furthermore, the architecture of the cloud platform and the deployment of applications over the platform is proposed together with considerations on its information security protection.