Embodiments of this application disclose a channel characteristic obtaining method and a related apparatus. The method includes: A first communication apparatus sends a first reference signal and a first notification message to a second communication apparatus; and the first communication apparatus receives channel characteristic information of a first channel type from the second communication apparatus. The first channel type is a channel type corresponding to first channel state information CSI determined by the second communication apparatus based on the first reference signal, the first notification message is used to request the channel characteristic information of the first channel type, a channel characteristic of the first channel type is from a channel characteristic library, and the channel characteristic library includes channel characteristics of one or more channel types. In this way, the first communication apparatus obtains the channel characteristic of the first channel type based on the channel characteristic information of the first channel type. This helps the first communication apparatus perform channel reconstruction, estimation, or the like based on the channel characteristic of the first channel type, to improve performance of communication between the first communication apparatus and the second communication apparatus.