The present invention relates to a butterfly filter coefficient setting method and device, a receiver, and a receiving method. The receiver is a DP-CO-OFDM receiver, comprising: a phase recovery device configured to perform a phase recovery of a received signal one OFDM symbol by one OFDM symbol, so as to obtain a phase-recovered first polarization signal and a phase-recovered second polarization signal; a butterfly filter configured to perform butterfly filtration of the phase-recovered first polarization signal and the phase-recovered second polarization signal one OFDM symbol by one OFDM symbol, so as to obtain a butterfly-filtered first polarization signal and a butterfly-filtered second polarization signal; a coefficient setting unit configured to set a filter coefficient used by the butterfly filter for the current OFDM symbol; and a data recovery device configured to recover data from the butterfly-filtered first polarization signal and the butterfly-filtered second polarization signal.