In order to reduce the bit error rate of visible light communication (VLC) systems, a VLC video transmission system based on binary on-off keying (OOK) modulation is designed. This system improves the system's bit error performance and expands the system's -3 dB bandwidth by using an improved 4B5B encoding and post-equalization amplification circuit, and realizes OOK demodulation by analyzing the correlation characteristics of the data based on adaptive threshold decision. The experimental results show that the system can achieve real-time, lossless transmission of 1 080 P high definition video at a distance of two meters. When the transmission rate is 60 Mb/s, the improved 4B5B encoding can reduce the bit error rate of the uncoded system from 2.2x102 to 2.81x10-6.