In ultraviolet (UV) scattering communication systems, pulse broadening and noise considerably affect the signal. To reduce system bit error rate and increase communication distance, it is necessary to add low-density parity check code (LDPC) to implement symbol error correction. The performance of on-off keying (OOK) modulation and binary phase-shift keying (BPSK) for subcarrier intensity modulation is compared. Further, the influence of LDPC codes with different coding efficiencies and decoding methods under BPSK subcarrier intensity modulation on the bit error rate of a non-line-of-sight (NLOS) ultraviolet communication system is simulated and analyzed. Results indicate that BPSK subcarrier intensity modulation performs better than OOK modulation. LDPC codes with low coding efficiency values exhibit strong error correction ability. The performances of belief propagation (BP) algorithms and log-likelihood ratio belief propagation (LLR BP) algorithms are virtually the same, and both are better than min-sum algorithms. When the bit error rate is 6.5 × 10 -6, the communication distance of the LDPC (672,168) coded sequence is approximately doubled, compared with the uncoded sequence.