Abstract: A high-ductility battery aluminum foil and preparation method thereof are disclosed. The high-ductility battery aluminum foil includes a first component and a second component. The first component includes Si, Fe, and Cu. The second component is Al. In a cross-section of the high ductility battery aluminum foil, a presence of iron-containing second phase with an equivalent circular diameter of 0.2˜3 ?m is in a range of 1.1×102˜4×104 particles/mm2. A presence of metal intermetallic compounds, with an equivalent circular diameter of 0.2˜3 ?m, formed by Si and Cu respectively with Al, is not greater than 1.1×102 particles/mm2. A presence of elemental silicon particles, with an equivalent circular diameter of 0.2˜3 ?m, is not greater than 1.1×102 particles/mm2. The high-ductility battery aluminum foil has a thickness not greater than 13 ?m, a tensile strength not less than 250 MPa, and an elongation not less than 5%.