Visible light communication is a burgeoning technology that uses the visible spectrum for high-speed short-range data communications. Intensity modulation/direct detection is predominantly used in optical wireless in which white LEDs serve as transmitters, neglecting frequency and phase of signal. Therefore correlation in optical channel is much larger than that in radio frequency channel. The factors which influence the correlation of the optical multiple-input multiple-output (MIMO) channel are analyzed, and the way these factors influence the channel correlation is validated through simulation. According to the mutual influence of signal-to-noise rate and channel correlation, optimal parameters can be obtained in specific scene for optimal bit error rate.