Embodiments of this application disclose a method for reporting CSI of a multi-hop path and a related apparatus. The method includes: The multi-hop path includes a first device, a second device, and a third device, where the first device is a source device, and the second device is a target device. The first device obtains a first CSI report of a target transmission path. The first CSI report indicates the target transmission path. According to embodiments of this application, so that a comprehensive channel state of the multi-hop path can be obtained from a data sending device, namely, the source device, by reporting first CSI.