Disclosed is a reference signal transmission method and a device. The method includes converting, by a sending device, a frequency domain reference signal from frequency domain to time domain, to generate a time domain reference signal. The frequency domain reference signal includes a reference signal sequence mapped to a frequency domain resource. The reference signal sequence is determined based on a Zadoff-Chu (ZC) sequence, and a length value of the ZC sequence is selected from at least two length values. The method includes sending, by the sending device, the time domain reference signal. According to the reference signal transmission method, one ZC sequence is selected from at least two ZC sequences with different lengths to generate the reference signal sequence, so that the generated reference signal sequence is characterized by a low PAPR and an low RCM, and is used to generate a reference signal, to improve data transmission performance.