The invention discloses a high-welding strength TPO (Thermoplastic Polyolefin) waterproof roll and a preparation method thereof and belongs to the technical field of waterproof building materials. A formula of the high-welding strength TPO waterproof roll is prepared by combining a metallocene olefin polymer, a TPO resin, a flame retardant, a filler, an antioxidant, a light stabilizer and pigments in certain parts by weight, wherein the formula comprises the following components in parts by weight: 10-50 parts of metallocene olefin polymer, 50-90 parts of TPO resin, 5-50 parts of flame retardant, 0-50 parts of filler, 0.01-5 parts of antioxidant and processing aids, 0.01-5 parts of light stabilizer and 0-8 parts of pigments, and the part number of the metallocene olefin polymer and TPO resin is 100. According to the invention, the welding strength of the TPO waterproof roll is improved, and the TPO waterproof roll has excellent energy-saving characteristic and weather resistance.