Abstract: The multi-array light source layout is usually adopted by the visible light communication (VLC) system to give consideration to both illumination and communication functions. Therefore, the MIMO technology is required for the multi-antenna cooperative transmission to achieve the high-rate communication. However, the average power allocation is used to achieve the spatial multiplexing in the traditional MIMO system, which cannot fully reflect the advantages of the MIMO multi-antenna coordinated transmission. Based on the differences for the state of receiving and sending antenna channel in each group, a fast iterative water-filling algorithm with low computational complexity was designed, which could realize the allocation information on the basis of channel feature adaption and improve the channel capacity of the system. Finally, the simulation results show that under the same SNR, the channel capacity of the adaptive power allocation system with water-filling algorithm is about 1.25 bit/HZ higher than that of the equal power allocation system.