The invention discloses a low-noise and low-spark micro-motor carbon brush and a preparation method thereof. The carbon brush comprises the following raw materials by weight: 30-80% of electrolytic copper powder, 0-7% of silicon carbide, 0-7% of chromic carbide composite material, 0-7% of tungsten carbide, 0-7% of silicon nitride, 0-7% of iron sulphide, 5-10% of high-conductivity material, 40-60%of adhesive and 20-60% of graphene powder. The preparation method comprises the following steps of S1, weighing the raw materials; S2, placing the raw materials into a mixing kettle and mixing; S3, pressing, placing the mixture into a press machine for obtaining a blank; and S4, performing high-temperature sintering of the pressed blank, and taking out for obtaining the low-noise and low-spark micro-motor carbon brush. The low-noise and low-spark micro-motor carbon brush and the preparation method thereof have advantages of improving product rigidity, improving self conductivity of the product, realizing low rigidity and satisfying a designed rotating speed requirement of the motor, realizing an effect of reducing mechanical spark and noise in a use process, and effectively controlling anoverhigh temperature increase condition.