Capacitive touch screen is taken on both sides of transparent conductive materials, cloth all-glass structure. In the screen around the distribution of the low-voltage, forming a low-voltage AC electric field. When the user touch the screen, the four sides of electrode current will flow into the issue of contact, resulting in a voltage difference. Current strength and finger to the electrode is proportional to the distance. In the touch screen controller will be based upon the ratio and the strength of current, accurate to calculate the contact (X, Y) position, and the results passed to the computer.