Light source layout is one of the key factors that affects indoor LED optical communication lighting and communication performance. Compared with the large divergence angle Lambertian LED used in the traditional layout, small divergence angle LED has the advantages of small reflection area and high central light intensity. This article uses LED with small divergence angle as light source, and aiming at the optimal uniformity of illumination and the minimum number of LEDs, the light source layout of square and rectangular rooms are optimized, and the system performance of the optimized layout is analyzed. The results show that the illuminance uniformity of the optimized layout in both rooms are greater than 90%, and the received optical power is also greater than -2 dBm. Moreover, in the square room, under the premise of reducing the number of LEDs by 16, the system performance is better than the traditional layout, the average illumination is improved by 7.7%, the average signal-to-noise ratio is improved by 0.89 dB, and the mean variance of signal-to-noise ratio is reduced by 0.04 dB.