The invention discloses an automobile rubber sealing strip and a preparation method thereof. The automobile rubber sealing strip comprises the following components in parts by weight: 55-80 parts of ethylene propylene diene monomer rubber, 4.5-8 parts of carbon black, 0.5-2 parts of zinc oxide, 1-2 parts of stearic acid, 3-5 parts of anti-aging agent, 0.5-1 part of ultraviolet-resistant agent, 1.5-3 parts of naphthenic oil, 3-8 parts of vulcanizing agent, 1.5-4 parts of accelerator, 1-2 parts of antioxidant, 1-2.5 parts of paraffin oil, 0.5-1 part of gamma-(methylacryloyloxy)propyltrimethoxy silane, 1.5-5 parts of filler and 0.5-1.5 parts of anti-scorching agent CTP. The automobile rubber sealing strip enhances the high temperature resistance, low temperature resistance, stability to light, ozone. oxygen and the like and other comprehensive properties of the product and improves the interface compatibility on the premise of keeping the original mechanical properties. The preparation method has the advantages of simple technique, short vulcanization time, lower energy consumption and lower production cost.