Abstract: Aiming at the problem of high data exchange overhead and inflexible bandwidth allocation between multi- virtual machines(VMs) on the same host, hardware supported methods of multi-VMs switching and dynamic bandwidth allocation are proposed. Based on the concept of IO virtualization, this method focuses on improving and optimizing the hardware architecture of Ethernet controller. By parsing the sending data of VM and extending the access authority of the sending engine to the receiving BD ring, the switching process from the sending engine to the destination VM is realized directly. Besides, through statistics and analysis of data of receiving queue in VM, the bandwidth of each VM can be dynamically allocated and adjusted. The experimental results show that the proposed methods not only reduce the CPU overhead of data exchange and bandwidth allocation between multi-VMs, but also maintains compatibility with Ethernet controllers and hypervisors.