This application provides a phase tracking reference signal (PTRS) sending method and apparatus. The method includes: implicitly determining, by a terminal device based on obtained uplink grant information and a preset rule, a to-be-sent PTRS and an antenna port for carrying the to-be-sent PTRS, where the antenna port is selected from an antenna port set, and the to-be-sent PTRS is one or more of all available PTRSs; and putting the to-be-sent PTRS on the antenna port, and sending the to-be-sent PTRS on the antenna port. This implicit indication method can effectively reduce air interface signaling overheads and improve air interface efficiency.