The pilot-aided method was adopted for estimation and compensation of sampling clock frequency offset in CO-OFDM systems to improve the system′s performance .And the pilot arrangements were simulated and discussed by comparing with five different location of pilots inserted,the optimal location of pilot inserted was obtained.The simulated results show that the method can work quite effectively even with large sampling clock frequency offsets,and the loss of optical signal-to-noise ratio is less than 1 dB.Therefore,it can reduce the cost of system;the location of pilots will impact the performance of the algorithm,the average insertion of pilots is optimal.With increasing sampling frequency offset,if the method can not work well,the pilots should be inserted at the low frequency sub-carriers.