The invention discloses a method for preparing a large touch screen. The method comprises the steps of S1, conducting aging on a first substrate and a second substrate which are used for preparing the touch screen separately, S2, providing a printer, printing a first matrix figure on the first substrate by using the printer, printing a second matrix figure on the second substrate, wherein paint of the printer is made of nano metal-doped UV ink, S3, separately irradiating the first substrate and the second substrate by using UV light so as to cure the UV ink, S4, coating the side, wherein the first matrix figure is printed, of the substrate with optical glue, and S5, attaching the first substrate to the second substrate so that the first matrix figure and the second matrix figure form a capacitance matrix. According to the method, since nano metal is adopted for preparing the matrix figures, the resistance of the matrix figures is greatly reduced, and even if the matrix figures are large, the resistance is also small; therefore, the sensitivity of the touch screen is guaranteed, and since the size is not limited, the large touch screen is supported.