This application provides a communication method and apparatus, and relates to the field of communication technologies. Including: determining a third carrier based on M first carriers and/or N second carriers, where one of the M first carriers is a carrier corresponding to one of M QoS flows, one of the N second carriers is a carrier corresponding to one of N PC5-S messages, and M and N are positive integers; and transmitting a PC5-RRC message on the third carrier. Because the second carrier corresponding to the PC5-S message and the first carrier corresponding to the QoS flow may meet requirements of a terminal device for transmission, the third carrier determined based on the first carrier and/or the second carrier may meet requirements of the terminal device for transmission of the PC5-RRC message.