The combination of orthogonal frequency division multiplexing (OFDM) technology, coherent receiver and digital singal processing (DSP) is one of the ideal models in long-haul communication. However, optical OFDM receiver is sensitive to phase noise, so it is necessary to compensate phase noise for optical OFDM systems. A joint phase equalization solution to optical OFDM system based on orthogonal wavelet transform is proposed. In this method, block pilots are periodically inserted into the frame of OFDM signals. At receiver, the phase rotations of pilots are extracted to eliminate common phase difference of each subcarrier. Then, an adaptive equalization is applied to eliminate the phase error inside each subcarrier. Simulation results demonstrate that the proposed method is effective for 100 Gb/s optical binary translation quadrature amplitude modulation (4QAM) OFDM system in which data transmitted over 1000 km with G.652 fiber.