A dual-wavelength transceiver separation method is proposed for the problem of self-interference limiting the system communication performance in Full-Duplex Underwater Wireless Optical Communication (FD-UWOC) systems. Based on the Monte Carlo numerical simulation, the effects of self-interference on the performance of 450 nm single-wavelength, 525 nm single-wavelength and dual-wavelength FD-UWOC systems are analyzed under three typical water qualities of Jerlov I, Jerlov IB and Jerlov II. The simulation results show that the poorer the water quality, the stronger the self-interference. It is also shown that the enhancement of self-interference will significantly reduce the Optical Signal to Noise Ratio (OSNR) of FD-UWOC, which limits the longest transmission distance of the system. The FD-UWOC system using the dual-wavelength transceiver separation method can bring about 60 dB improvement in OSNR compared with the single-wavelength FD-UWOC system, which can achieve a longer transmission distance. An 80 m improvement in Jerlov II water quality, and an effective transmission distance of more than 100 m in Jerlov I and Jerlov IB water quality are achieved. These results provide some reference significance to the design of FD-UWOC system.