High phase noise and low phase noise have been consideration in CO-OFDM systems, respectively. The hybrid mitigation algorithm is optimized to approach to high phase noise and low phase noise environment, and a hybrid half-blind phase noise compensation algorithm is proposed, which could be suitable to shifty DFB laser linewidth. 4QAM and 16QAM are used to modulate binary signal. The new proposed phase noise compensation algorithm is considered a mitigation method which has the ability of half-blind self-adaptation. It deduces the coefficient matrix in high and low phase noise compensation matrix and could improve performance under high or low modulation index situation.