Tempered glass is a kind of safety glass, the normal glass is strengthened by chemical or physics method. During tempering, stress forms on the surface of the glass. Stress of the top layer offset while bearing external force, which improves bearing capacity and the tensile strength. There are two major advantages of tempered glass, first, the intensity improves several times compared to the ordinary glass, the bending strength is 3 times and shock strength is 5~10 times of ordinary glass, security is also improved while intensity is improved. The second major advantage of tempered glass is safety. Its bearing ability is increased and it becomes harder, though it is crushed, the fragment presents without acute angle so that it avoid hurting human body. The heat shock endurance of tempered glass is 2 times compared with ordinary glass and can generally bear difference in temperature of more than 150℃, which effectively prevent hot to bomb.