A phase noise inter-carrier interfere nce (ICI) suppression algorithm based on the Wiener filter is proposed so as to solve the ICI problem caused by the phase noise in the coherent optical o rthog onal frequency division multiplexing (CO-OFDM) communication systems.The proposed algorithm can effectively suppress the effec t of the ICI at the condition of the large phase noise.This algorithm can be deduced and obtained by the structure principle of the Wiener filter and does not need to change the original structure of the OFDM symbol.Moreover,the algorithm just requires to us e the statistical data obtained by the phase noise in advance and can get the ICI correction term through the related calculation.Bec ause there is no additional auxiliary data in OFDM symbol,the proposed ICI suppression algorithm,compared with the ICI self-cancel lation algorithm,has higher spectrum utilization. The proposed algorithm is comparatively analyzed with the ICI cancellation algor ithm based on the iterative detection.The simulation results show that the proposed ICI suppression algorithm can effectively suppres s the ICI,reduce the error floor and improve the performance of the bit error rate (BER) while the bit er ror rate of the ICI cancellation algorithm based on the iterative detection tend s to 10－4 and the error floor occurs at the phase noise rate of 10－4.