Digital twin technology plays a crucial role in advancing intelligent manufacturing and industrial Internet applications, particularly in automotive research, development, manufacturing and services. Creating a digital twin of a vehicle serves as a foundation for implementing this technology in the automotive industry. In the paper, we explore the architecture of a vehicle digital twin system, discuss the construction of physical and virtual entities within it and the connections between them. And then we propose a vehicle digital twin design scheme for anomaly detection in Controller Area Network (CAN). Specifically, we first create a virtual vehicle model and a vehicle powertrain CAN bus model, and then deploy a vehicle digital twin system. During the construction process, Simulink modeling and Simulink/CANoe co-simulation modeling are utilized. Finally, we design an experiment to detect and address various CAN bus attacks to verify the effectiveness of the digital twin system.