This paper investigates the impact of channel coding on the physical layer security of bidirectional chaotic optical communication. We construct a system model incorporating legitimate endpoints and eavesdropper (Eve), and utilize the information leakage rate (ILR) as a security evaluation metric. We analyze information leakage under un-coded, Reed-Solomon (RS) encoding schemes, specifically RS(255,239) and RS(255,223), at different eavesdropping locations and parameter mismatches. The simulated results show that under conditions of proximal eavesdropping or minimal synchronization error, the ILR of the coded system exceeds the uncoded system. Conversely, as the eavesdropping distance increases or the parameter mismatch becomes significant, the ILR of the coded system decreases rapidly and approaches zero.