A channel prediction method and a related device, where the method includes: obtaining a first channel coefficient sequence in a first time period, where the first channel coefficient sequence includes a plurality of complex values of a channel coefficient; and determining a prediction value of the channel coefficient in a second time period based on the first channel coefficient sequence and a preset vocabulary of channel changes, where the preset vocabulary of channel changes includes a mapping relationship between a channel change value index and each change value of the channel coefficient, and where the second time period is later than the first time period.