Automotive controllers need a full range of functional tests before actual use, including the interaction testing between controllers and external IO signals as well as the data communications testing with other powertrain components. A modelbased residual bus simulation platform was developed with PXI realtime controller based on NI Veristand and the main components of electric vehicles were modeled. The built model could simulate the data communication and the input and output status between the controller and other automotive components in realtime. Through observing data communication timing diagrams from the platform, the signal delays and other communication failures of tested controller could be found. Finally, the practical application of residual bus simulation platform to the realtime communication between battery management system (BMS) and virtual charger during charging and discharging was described. The experimental result shows that this method can effectively reduce the number of real tested components and lower the complexity of the entire test system, cutting significantly the cost of new energy vehicle controller system test.