Based on the analysis of the roles of smart rolling stock in smart urban rail transit system, architecture relationship diagrams were depicted from the view of the rolling stock side; The important study aspects about onboard equipment were pointed out, the functions as well as the realization conceives of rolling stock operation and maintenance system and safeguard system were proposed; These two systems should include onboard part and ground part were indispensable and were to be merged into the smart urban rail transit cloud system. By analyzing the interaction betw