The embodiment of the invention provides a container network construction method and device, a physical host and a data transmission method, and the construction method comprises the steps: building avirtual network interface in the physical host, and distributing the built virtual network interface to a virtual host deployed in the physical host; configuring the virtual network interface to a network namespace of a container instance deployed in a virtual host machine; and configuring a forwarding rule based on the virtual network interface. Based on the container network constructed by themethod, the container instance directly transmits data to a virtual switch or a physical network interface on a physical host where the container instance is located through a virtual network interface configured to a network namespace of the container instance; and the physical host forwards the data received from the virtual switch or the physical network interface according to the forwarding rule configured based on the virtual network interface, so that when data is transmitted between the container instance and the virtual switch or the physical network interface, intermediate forwardinglogic is omitted, and the performance of the container network is improved.