Information leakage, which damages the transmission medium in optical communication systems, is becoming increasingly serious. The existing optical communication systems can easily expose data to unauthorized users, specifically when malicious users control the target demodulator. Therefore, based on the alliance chain, the data are encrypted first based on the elliptic curve encryption algorithm and the signature algorithm, and then they are transmitted through the optical network system. Thus, a blockchain-based optical communication security transmission system scheme is proposed. The scheme has a high modulation and demodulation efficiency, fast operation speed, and verifiability. The theoretical analysis and experimental results indicate that the scheme has better security and high performance, and it generates the security requirements of optical communication systems during data transmission.