The present invention provides a demodulation reference signal transmission apparatus, system, and method. The method includes: sending, by a base station, a configuration indication to user equipment UE, where the configuration indication is used to instruct the UE to send an independent DMRS and/or instruct the UE to send a combination of a DMRS and uplink data; and subsequently receiving, by the base station, the independent DMRS sent by the UE; and/or receiving the combination of the DMRS and the uplink data sent by the UE. In this way, the base station can trigger the UE to send the foregoing DMRS to complete frequency offset estimation, thereby improving accuracy of the frequency offset estimation.