A channel estimation method, a related device, and a system are described. A method for channel estimation may include determining when there is a damaged cell measurement reference signal (CRS) in a plurality of CRSs in target resource blocks (RBs), where the target RBs are RBs in compressed standard bandwidth. The method may also include performing, by a terminal, channel estimation by using an undamaged CRS instead of the damaged CRS in the plurality of CRSs. Based on the method, accuracy of channel estimation can be improved, and a problem of a relatively large error of a demodulation result of a data demodulation service performed based on the channel estimation result is resolved.