ing at scenes with large laser frequency offset,we study an integer frequency offset estimation and compensation method for a coherent optical offset quadrature amplitude modulation based filter bank multicarrier (CO-FBMC/OQAM) system. We expand previous researches and investigate the fractional frequency offset (FFO) by designing a hybrid training sequence structure. Based on this training sequence, we can precisely estimate the FFO and effectively implement the integer frequency offset (IFO) estimation. Further, numerical simulations are used to examine the effectiveness of the proposed method with respect to the CO-FBMC/OQAM system. The results denote that the maximum IFO can be accurately estimated to be 12 times that of the subcarrier frequency interval and that the bit error rate after frequency offset compensation is lower than the forward error correction limit. The proposed method can provide a useful reference for the research and development of the CO-FBMC/OQAM system.