Brief IntroductionIn order to produce fire retardant magnesium hydroxide, it must be fine crystal shape, small average particle size, small specific surface area, prone to decentralize, hard to reunite and surface polarity eliminated. Adopt synthesized techniques on magnesium chloride as raw material, treat magnesium hydroxide with hot water, and then make it a fire retardant which can be used in plastic and rubber through surface treatment to have the characteristic of low initial decompose temperature and 10% more heat absorptivity compared with aluminium hydroxide. It can be applied in PE, PVC, PP, and also in PET, PBT, PA, PPO, and ABS and so on. Our tenet is to develop fire retardant magnesium hydroxide of wide range of application.