A data transmission method and a network device are provided. The method can include: determining, by a first network device, that a terminal device enters an RRC inactive state; sending, by the first network device, a first message to a second network device, where the first message is used to configure the second network device, so that the second network device transmits data for the terminal device in the RRC inactive state; and receiving, by the first network device, an acknowledgment message the first message and sent by the second network device. The second network device can transmit data of the terminal device to the first network device to enable the first network device to send the data to a core network, without having to establish a path between the second network device and the core network for the second network device to send the data to the core network.