In visible light communication multiple-input multiple-output (VLC-MIMO) system, the increasing of sender and receiver elements, the decreasing of array element space, and the increasing of transmission distance cause a series problems of serious interference on receiver of the system and lack of channel matrix, and further lead to low reusing rate of the system and large channel correlation. To solve these problems, the minimizing of interference-to-signal ratio is taken as the optimization goal. The channel model of VLC-MIMO is established, and the effects of the normal vector tilting angles of sender and receiver elements on channel correlation are analyzed. The normal vector tilting angle of light-emitting diode is optimized to decrease the channel correlation, and the optimal tilting angle of the normal vector tilting angle of each LED is obtained. By comparing the illumination distribution on the receiving plane of the system, we find that the proposed scheme can effectively reduce the interference, and the bit error rate is reduced by 42 dB compared with that of the link-blocked system.