The invention discloses a surface modification method for a medical grade silicon rubber. The surface modification method is an ion implantation method, the implanted ions are C ions, and the ion-implanted material to be modified is the medical grade silicon rubber; in the process of ion implantation, the ion energy is 5 to 10kev, the using amount of ions is 1.0*1,014 ions / cm<2> to 1.0*1,016 ions / cm<2>, the beam density is no more than 0.6 mA / cm<2>, and the residual gas pressure is no more than 1*10<-3>Pa; and in the surface modification method, the C ions serving as the major elements of the human body are selected as the implanted ions, so that the hydrophily of the surface of the silicon rubber, namely the affinity with an organism, is enhanced, and the silicon rubber after being implanted into the human body can be comparable with histocytes, and the deformation and displacement of a medical silicone rubber implant are avoided. Meanwhile, the surface modification method of the invention overcomes the defects of poor peeling, poor stability and complicated processing steps, and the like existing in conventional plasma treatment, graft copolymerization and bionic coating, and the like.