ing at the multi-carrier filter bank transmission system for coherent optical offset quadrature amplitude modulation (CO-FBMC/OQAM) technique, a pilot-based time-domain phase noise compensation algorithm is proposed. A time-domain phase noise compensation model is established, that is, phase noise is approximated by time-domain extended discrete cosine transform (DCT). Phase noise includes common phase error (CPE) and non-CPE phase noise, which can be obtained by estimating DCT coefficients. In order to calculate these DCT coefficients, the CPE is estimated by pilot-based extended Kalman filter (EKF). Then, some of the data with high error probability after CPE compensation are discarded, and only the remaining CPE compensation data are retained for pre-decision to predict the sender data. Finally, the proposed algorithm is simulated and verified in a back-to-back CO-FBMC/OQAM system with a baud rate of 32 GBaud. The results show that compared with an improved phase search (M-BPS) algorithm, the spectral efficiency of the proposed algorithm decreases by 0.5%--2.0%. For 64-order QAM systems with subcarriers M=256 or 512, the linewidth delay product tolerance of the proposed algorithm is still much larger than that of the M-BPS algorithm, but its complexity is only half that of the M-BPS algorithm.