A CSI-RS transmission method and a network device are provided, to resolve a technical problem that very large pilot resource overheads are occupied for sending CSI-RSs, and reduce pilot transmission resources occupied for sending CSI-RSs, to reduce pilot transmission overheads. The method includes: determining, by a network device, that at least two of M quantities of antenna ports respectively used by M radio remote units RRUs for sending a CSI-RS to same user equipment are not equal, and instructing the M RRUs to send P CSI-RSs on N resource elements, where at least one of the N resource elements carries content of at least two of the P CSI-RSs, the P CSI-RSs are CSI-RSs respectively sent by P RRUs in the M RRUs, M is an integer greater than or equal to 2, P is an integer less than or equal to M, and N is a positive integer.