An Optimization Residual Frequency Offset Tracking Method for 802.11a/g/n System is proposed in this paper.The residual frequency offset tracking is done in the frequency domain using the pilot of the ofdm data zone is the basic strategy.The key ideals of the method are estimating the increment phase step by step

and getting the phase′s average for the summary of the incremental phase

getting the final value through iterative adding

which decrease the effect from the noise

and solving the problem when the phase is beyond -π

π

the system link level simulation result proves that the method can improve the ber of the ofdm system effectively.