The traditional LED layout has the problem of uneven illumination in indoor visible light communication(VLC) system, which brings blind effect with communication. To solve these problems, we propose a light source LED optimization scheme that considers wall reflections and analyze LED layout by using the mean square error of illumination as evaluation criterion. Then, the expressions of received illumination and power are deduced by integrating, which are used to build optimization model function F(l,x,y) of rectangular layout and optimization model function F(r,x,y) of circular layout. The relationships between the mean square error of illumination and the room size, and between the optimal layout and field of view ψFOV are researched based on optimization model function. It is clear from the results that the F(l,x,y) can reach the minimum value when l=1.6 m and ψFOV=80°, and the illumination uniformity is increased from 80.5% of traditional layout to 84.3%; the F(r,x,y) could also obtain the minimum value when r=2 m and ψFOV=80°, and the illumination uniformity is increased from 85.2% to 89.2% with the increase of the number of LED.