A radio communication method and a terminal device are provided. In a D2D communications system, the terminal device may determine an RAT for transmitting data, so as to ensure reliable transmission of the data. The method is applied to device-to-device communication through a PC5 carrier comprising obtaining configuration information indicates a correspondence between identifier of services and at least one Radio Access Technology (RAT) that comprises a plurality of access layer parameters, determining, at least one access layer parameter for transmitting a first service according to the configuration information, wherein the first service belongs to the at least one service, and transmitting the first service by using the at least one access layer parameter.