Aiming at the problem of harsh information synchronization conditions in optical chaotic confidential communication, a bidirectional communication system based on optical chaos is proposed. First, two laser beams emitted by a semiconductor laser（SL） are coupled with a partially translucent optical mirror to generate chaotic power, and the internal parameters of two SLs are set to generate synchronous chaotic carriers according to the delay rate equation of SL. Then, the decryption signal is obtained by monitoring the synchronization error of the signals at both ends and comparing with the signals at the receiving end. The synchronization, signal decryption process and robustness of the system are simulated and analyzed. The simulation results show that the system can realize synchronous communication, recover the secret signal and has good robustness.