The invention provides a foil blank for a new energy battery and a preparation method of the foil blank. The foil blank comprises the following components, by mass, less than or equal to 0.1% of Si, 0.1-0.25% of Fe, 0.03-0.05% of Cu, less than or equal to 0.05% of Mn, less than or equal to 0.05% of Zn, less than or equal to 0.05% of Ti and the balance Al. The preparation method comprises the steps of (1) smelting, (2) turning down, (3) degassing, (4) deslagging, (5) cast rolling, (6) plate shape control and (7) quality inspection. According to the prepared foil blank for the new energy battery, the tensile strength is larger than or equal to 260 MPa, the ductility is larger than 3%, and the number of pinholes is smaller than or equal to 100 / m < 2 >; while the mechanical performance of the blank is guaranteed, the number of pinholes is small, the strip breakage rate is low, the machining performance is excellent, and the quality of a finished product can be remarkably improved; and compared with a traditional hot-rolled material, the production process is short, and the cost is low, so that resources and energy are saved, and the machining efficiency of products is improved.