Embodiments of the present invention provide a method and an apparatus for transmitting a reference signal and a method and an apparatus for receiving a reference signal. The method includes: determining, by a terminal device, sequence information of a first sequence set corresponding to a first reference signal and information about a first resource used for transmitting the first reference signal, where the first sequence set includes at least one sequence, the information about the first resource includes time domain information of the first resource and/or frequency domain information of the first resource, and a first mapping relationship exists between the sequence information of the first sequence set and the information about the first resource; and transmitting, by the terminal device, the first reference signal based on the sequence information of the first sequence set and the information about the first resource. This can reduce signaling overheads during uplink transmission, improve utilization efficiency of system resources, and improve system reliability.