The invention relates to a method for increasing the power frequency breakdown electric field intensity of addition type liquid silicone rubber. The method is characterized in that vinyl silicone oilis taken as a base polymer, hydrogen-containing silicone oil is used as a crosslinking agent, and white carbon black is taken as necessary reinforcing filler; the crosslinking density of the additiontype liquid silicone rubber is improved by increasing the content of a platinum catalyst in a formula, so that the power frequency breakdown electric field intensity of the addition type liquid silicone rubber is improved. After the preparation method provided by the invention is adopted, not only is the addition type liquid silicone rubber with excellent power frequency breakdown resistance obtained, but the mechanical properties of the addition type liquid silicone rubber are also maintained, so that the requirements of an injection molding technology or a pouring technology can be met.