The invention relates to a method for preparing rubber master batch, which is applied to the technical field of anti-corrosive pipes. The rubber master batch is prepared from the following components in parts by weight: 12.5-13.5 parts of styrene butadiene rubber, 1.5-1.6 parts of nature rubber, 9.5-10.5 parts of kaolin, 11.5-12.5 parts of light calcium carbonate with average grain diameter of 1-5 microns; 3.0-3.5 parts of No. 40 engine oil, 1.5-2.0 parts of ethyl acetate and 2.0-2.5 parts of dioctyl phthalate. The method comprises the following step of: putting mixed raw materials into a rubber grinding machine to be ground to form the rubber master batch with the thickness of 1.5-2mm. The method for preparing the rubber master batch has the advantages of improving cold resistance of pressure-sensitive adhesive produced by adopting the rubber master batch to 8-12 DEG C, modifying the performance of the pressure-sensitive adhesive carried on anti-corrosive rubber, enabling the water vapor transmittance to be lower than 0.45mg/cm<2>, improving the anti-corrosive waterproof effect and enabling the water absorption to be lower than 0.30%.