In the field of communications, a method for improving signal quality, a pre-correction bit error rate feedback device, and an OTN apparatus are provided, which are capable of improving quality of each channel of signals demodulated by the optical module. A solution is: collecting a statistic of an error correction bit rate of data bits of a signal corresponding to each virtual channel during FEC decoding, calculating a pre-correction bit error rate of a physical channel corresponding to each virtual channel according to the error correction bit rate of the data bits of the signal corresponding to each virtual channel, feeding back the pre-correction bit error rate to a receiving optical module, and adjusting, by the optical module, a receiving parameter of each physical channel to reduce the pre-correction bit error rate of each physical channel.