A method includes: receiving, by a terminal, at least one piece of first transmission resource pool configuration information sent by a network device, where the first transmission resource pool configuration information includes at least a first transmission resource pool identifier and first transmission resource pool resource configuration information; when the terminal determines that a first transmission resource pool corresponding to the first transmission resource pool identifier is in a first state, independently selecting, by the terminal, a direct link transmission resource from time-frequency transmission resources corresponding to the first transmission resource pool resource configuration information; and sending, by the terminal, direct link service data by using the direct link transmission resource.