In coherent optical orthogonal frequen cy division multiplexing (CO-OFDM) system,the variance of the phase noise becom es larger when line-width of the laser increases,which can introduce m ore inter-carrier interference (ICI) in frequency domain and severely degrade the performance of the system.In addition,CO-OFDM s ystem becomes more sensitive to phase noise when the modulation format order is increased.In order to decrease the influence of the phase noise in systems which employs the larger line-width laser and the higher order modulation,a no vel three-stage phase noise compensation algorithm based on Kalman filtering is proposed.The novel algorithm is divided into three stages:coarse phase noise compensation in time domain,residuary common phase error (CPE) suppression in fr equency domain and fine phase noise compensation in time domain.The mathematical model of the algorithm is given ou t.Mentor-Carol simulations are researched on the models.The simulation analysis shows that the proposed algorithm,compared with several phase noise suppression algorithms,has the lower bit error rate (BER) at a large laser line-width and can improve the system′s tolerance of the laser line-width.