The invention discloses preparation of a brake pad lining of a disc brake. The brake pad lining comprises the following raw materials in parts by weight: 5-10 parts of steel fibers, 15-30 parts of barium sulfate, 10-20 parts of copper powder, 10-20 parts of modified cashew nut shell oil, 2-5 parts of aramid fibers, 2-5 parts of aluminum oxide, 2-5 parts of zircon, 0-5 parts of graphite, and 1-3 parts of mica. The invention further discloses a preparation method of the brake pad lining of the disc brake. The brake pad lining of the disc brake uses the modified cashew nut shell oil of phenolic resins as a binding agent of a friction material; a friction plate is located under high-temperature working condition of about 200-450 DEG C; the defects of heat fade, thermal expansion and thermal cracking phenomenon due to bad change of resins or rubber as the binding agent at the temperature in the prior art are overcome; and the use stability of the new material and the safety of the brake are guaranteed.