Regarding the strong correlation between channels that may be caused by dense layouts of transmitters and receivers in indoor multiple-input multiple-output visible light communication systems, which can lead to inter-channel interference and significantly affect communication quality, a challenge that is addressed by proposing the application of lattice basis reduction techniques to indoor visible light communication systems.By implementing a reduction operation on the visible light channel to reduce the correlation between channels, and applying the reduced channel matrix, combined with the zero forcing criterion and the minimum mean square error criterion, precoding design is carried out at the transmitting end. The simulation experiment results show that the application of lattice reduction technology can effectively improve the orthogonality of indoor visible light channels, and the more transceivers there are, the more obvious the improvement effect on channel correlation. The application of zero forcing criterion and minimum mean square error criterion can effectively improve the system's error rate performance.