The invention relates to a colored stainless steel based on ion implantation and a preparation method thereof. The technical scheme is as follows: placing a stainless steel to be colored in a vacuum chamber of an ion implantation apparatus, vacuumizing to 0.1-1*10<-5>Pa, and implanting ions on the surface of the stainless steel to obtain the colored stainless steel, wherein the accelerating voltage for ion implantation is 10-100kV, and the ion implantation amount is 1*10<17>-1*10<19> ions / cm<2>; or placing a stainless steel to be colored in a vacuum chamber of an ion implantation apparatus, vacuumizing to 0.1-1*10<-5>Pa, and implanting ions on the surface of the stainless steel, wherein the accelerating voltage for ion implantation is 10-100kV, and the ion implantation amount is 5*10<15>-5*10<19> ions / cm<2>; and taking out, carrying out heat treatment, and cooling to room temperature in the furnace to obtain the colored stainless steel. The invention has the advantages of simple process and clean environment, and the obtained colored stainless steel has the characteristics of multiple color varieties, high reproducibility, uniform color, beautiful appearance, high durability and no separation. Compared with the stainless steel prior to preparation, the surface hardness and the corrosion resistance are obviously improved.