A method, a device, and a system for triggering a scheduling request (SR) to meet quality of service (QoS) requirements of different services in a New Radio (NR) vehicle to everything (V2X) system and to avoid or reduce unnecessary SR triggering. The method includes that a network device sends a first message to a terminal device, where the first message includes a first identifier and one or more configuration parameters corresponding to the first identifier. The first identifier is of a first logical channel, and the first logical channel is of a sidelink (SL) radio bearer. Alternatively, there is a mapping relationship between the first identifier and the first logical channel.