The invention provides a die-casting aluminum alloy button and a preparation method thereof. The preparation method provided by the invention comprises the following steps: a) performing pressure casting and blank preparation on aluminum alloy to obtain a die-casting aluminum alloy blank; b) performing anodic oxidation treatment on the die-casting aluminum alloy blank to obtain a treated button blank; and c) performing dyeing and hole sealing treatment on the treated button blank to obtain the die-casting aluminum alloy button, wherein in the step a), the aluminum alloy comprises the followingcomponents in percentage by mass: 0 to 1.8 percent of Mn, 0 to 4 percent of Mg, 0 to 1 percent of Zn and the balance of Al; and not both of the Mn content and the Mg content are zero. According to the preparation method provided by the invention, the die-casting aluminum alloy button with bright, clean and flat surface and good dyeing effect and capable of dyeing can be successfully obtained by adopting specific aluminum alloy die-casting formation, adopting anodic oxidation treatment and adopting dyeing and hole sealing processes; and compared with the existing die-casting zinc alloy cotton,the cost of the die-casting aluminum alloy button greatly is reduced.