This paper proposes a backlight system that generates the regular dot pattern on the bottom of light guide to achieve uniform luminance. The simulation program employs the variable r-cut technique combined with some regular dot pattern such as shift-rectangular, hexagonal and so on. The r-cut technique based on molecular-dynamic method, was first bought up to apply in the random dot pattern. By using such a technology, we could easily evaluate the right range of radius within each cell to get the general dot distribution according to the specific position away from light sources and the sources properties, after we divided the total effective domain into several sections of cells. In the end we made some fine-tuning on the boundaries to obtain the final result. It has been revealed in the simulation that the light guide can achieve a uniformity of more than 90% and optical efficiency about 26%. What we have more interest in are the optical properties that have much influence on both the uniformity and the optical efficiency. Particularly when it comes to larger size backlight products used in PC screen for instance, it will have a great impact. Several figures in this paper also illustrate the dots distribution and the illuminance distribution.