The reference signal sending method includes: determining, by a first sending device, a first reference signal and a first code resource, where the first code resource is orthogonal to a second code resource, the second code resource is used to transmit a second reference signal; and sending, by the first sending device, the first reference signal by using the first code resource, where the first reference signal is carried on at least one first time-frequency resource group, a value of a quantity of resource elements (REs) occupied by each of the at least one first time-frequency resource group is the same as a value of a length of the first code resource, and the first reference signal and the second reference signal are multiplexed on a time-frequency resource occupied by the at least one first time-frequency resource group, based on the first code resource and the second code resource.