Embodiments of this application provide a data transmission method and a host machine, so that when a host machine cannot directly connect to the Internet, a virtual terminal can still connect to a mobile network. This extends an application scope of the virtual terminal. The host machine obtains a first network address of a physical terminal, where the physical terminal has started to establish a connection or has established a connection to the mobile network; and the host machine sets a second network address of the virtual terminal to the first network address, so that the virtual terminal sends data to the mobile network by using the first network address and/or receives, by using the first network address, data sent by the mobile network. The virtual terminal runs on the host machine.