In order to improve the bit error rate of the system, reduce the baseline drift and the absorption scattering of the seawater channel and other characteristics on the optical signal, a low density parity check (LDPC)-Reed Solomon(RS) cascaded interleaving code scheme based on the underwater light-emitting diode(LED) optical communication system was adopted. Under the simulated underwater LED optical communication experimental system, the effects of RS code, LDPC code, and interleaved parameters on the bit-error rate performance of the system were analyzed in the code scheme, and the optimized parameters of the cascaded interleaving code scheme were obtained and verified by the experimental simulation. The results show that the gain of 3.8dB, 2dB, and 1.2dB can be obtained with the optimized cascaded interleaving code system, compared with the uncoded system, RS code system, and LDPC code system, respectively, which can effectively improve the bit error rate performance of the system. This study provides a reference for improving the reliability of the underwater wireless optical communication system.