Three kinds of phenols, namely gallic acid, syringal alcohol and ferulic acid, were selected as laccase natural mediator to investigate the changes of fiber surfaces, morphological properties of fibers, kappa number and physical properties of OCC (Old Corrugated Containers) pulp with laccase/ natural mediator system treatment. It was illustrated that condensation reaction of phenols could be occured by catalytic oxidation of laccase. The results of fiber quality analysis and SEM observation showed that after treated using laccase/ natural mediator system, the resultantly yielded OCC pulp had much smoother surface, larger fibers coarseness, higher kappa number, and the auto-adhesion of fibers could be observed in the fibers. In additon, the wet strength of handsheets, especially the wet ring crush strength, was improved obviously, compared with control sample.