Toughened windshield in no direct external mechanical forces under the effect of the crack happens automatic called toughened glass explode oneself. Explosive is toughened glass of inherent characteristics of one. To create the glass the causes of the explosion many, simply summarized the following kinds, the first glass quality defect of influence. There is stone in glass and impurity: glass impurity is a weak point of toughened windshield, also is the stress concentration place. Especially if the stones in toughened glass tensile stress area is the important factor to burst. The windscreen safety performance is very important. Let alone if the safety performance of low degree of danger of crew body, and the car itself, if the wind glass cracks or file have obvious flaws, like face was scratched, serious damage to the appearance of the image. Therefore, the windshield safety requirement is very high. So we should give it enough focus to its healthy.