This research uses fiber, yam and fabric of Kevlar soak in sea water, bleach and detergent for 12 month. To analyze the reason of fabric damages and change of the bullet-proof caused by damages of fiber and yam of Kevlar in sea water, bleach and detergent for 12 month. Based on the experimental results, fiber, yarn, and fabric of Kevlar in sea water, bleach and detergent for 12 month. The breaking strength increases and reduces with soaking time, make CO bond has be changed, crystal has be broken, and make the bullet-proof has be subjected.
