The invention discloses a silicone rubber for a composite insulator, wherein the silicone rubber comprises the following raw materials in parts by weight: 30-50 parts of methyl vinyl silicone rubber A, 50-70 parts of methyl vinyl silicone rubber B, 25-50 parts of fumed silica, 100-130 parts of aluminium hydroxide, 1-6 parts of silane coupling agent, 0.2-2 parts of ultraviolet absorber, 2-6 parts of zinc oxide, 0.5-3 parts of triethanolamine, 0.2-1 parts of stearic acid, 0.5-2 parts of hydrogen-containing silicone oil, 0.2-1 parts of vinyl silicone oil, 0.5-3 parts of color masterbatch rubber, 2-6 parts of hydroxyl silicone oil and 0.5-1 parts of vulcanizing agent. The silicone rubber provided by the invention can achieve the following performances: the tensile strength is larger than 4 MPa; the breaking elongation is larger than 350%; the peel strength is larger than or equal to 12 KN.m<-1>; the shore hardness is 60+ / -5 degrees; the thermal aging tensile strength retention is larger than or equal to 90%; the anti-creep track passes a grade of 1A4.5; the flame retardance reaches a grade of FV-0; the average static contact angle is larger than 105 degrees; the electrical surface resistivity is larger than 2*10<15> omega; the dielectric constant is smaller than 3.8; and the dielectric loss angle tangent is smaller than 0.01.