The new indoor location method based on visible light communications has irreplaceable advantages over traditional wireless location methods. As for the new location method, the light distribution has direct impact on the location performance. In the condition of meeting the indoor illumination requirements, the cramer-rao bound (CRB) and the optimal light distribution with the best location performance in a typical simulation environment is inferred, after that, simulation analysis is given using the Gauss-Newton algorithm, and the results demonstrate the validity of the theory.