This application provides a reference signal generation method, a reference signal detection method, and a communications apparatus, so that a terminal device or a network device can generate a reference signal by using a pseudo-random sequence initial factor cinit provided in embodiments of this application. Compared with a solution in the current technology, the generation manner can support a relatively large quantity of reference signal sequences, to better meet requirements of a plurality of 5G scenarios. The method may include: obtaining a reference signal sequence based on a pseudo-random sequence initial factor cinit; and mapping the sequence to one or more OFDM symbols, where the pseudo-random sequence initial factor cinit is related to a parameter d, d max(log2(nID,max+1)−10,0) or d=max(log2 (nID,max+1)−12,0), max represents that a larger value is selected from two values, and nID,max represents a maximum value of a reference signal sequence ID.