The invention provides a sealing strip coating rubber and a preparation method thereof, and a car door sealing strip and a preparation method thereof. The sealing strip coating rubber is prepared from the following components parts by weight: 50-70 parts of ethylene propylene diene monomer rubber K8340A, 60-100 parts of ethylene propylene diene monomer rubber K4551A, 5-7 parts of zinc oxide, 1 part of polyethyleneglycol PEG-4000, 2 parts of stearic acid, 1 part of dispersing agent WB16, 1.4-1.6 parts of ultraviolet absorbent, 9-11 parts of high-polymer polyethylene wax, 4-6 parts of black factice, 0.7-0.9 part of foaming agent AC, 90-130 parts of carbon black SP5000, 40-6 parts of light calcium carbonate, 30-50 parts of paraffin oil P-2286T, 8-12 parts of moisture absorber CaO, 5-7 parts of accelerator and 1.0-1.4 parts of sulfur. The sealing strip coating rubber can be coated on the outer side of the sealing part in the existing car door sealing strip, and can overcome the defects in the existing gelatin-sponge-structure sealing part.