The invention relates to a preparation method of a copper-based friction material of a brake pad. The preparation method comprises the following steps of step 1, preparing of raw materials; step 2, mixing and granulating; step 3, cold pressing and forming; step 4, preparing of steel back; step 5, cold assembly and matching; step 6, placing and charging into a furnace; step 7, hot pressing and sintering; step 8, discharging out of the furnace, and inspecting. The copper-based friction material has the advantages that by adopting the coarser flaky graphite, the dust pollution is reduced; by adding a compound anti-abrasion component, the comprehensive property of the friction material is favorably improved; by adding a certain ratio of glycerol mixed solution, rolling by hands, stirring and granulating, the uniformity and stability of each component are guaranteed, the fluidity is good, the density distribution of the press billet is uniform, and the strength of the prepared press billetis high; by adopting the high-temperature pressurizing sintering parameters, the property requirement of the friction material is guaranteed, and the connecting strength with the steel back is also guaranteed; the technology process is simple, the cost is low, the production efficiency is high, the brake noise is avoided, the heat attenuation is little, the bonding strength between the steel backand a friction block is high, and the comprehensive property is good.