1. A display driving method for driving a stereoscopic display device, the stereoscopic display device comprising a pixel array and a grating provided on a light outgoing surface of the pixel array, the pixel array comprising a plurality of first pixel units used for displaying a first view and a plurality of second pixel units used for displaying a second view, the plurality of the first pixel units and the plurality of the second pixel units being arranged in a matrix and the first pixel units and the second pixel units being arranged alternately both in a row direction and a column direction, and each of the first pixel units and the second pixel units comprising a plurality of sub-pixels of different colors provided in a same column, the grating comprising a plurality of light shading regions and a plurality of light transmitting regions provided alternately both in the row direction and the column direction, each of the light shading regions being configured for shading a first region of the first pixel unit and a second region of the second pixel unit opposite to the first region of the first pixel unit which are adjacent in the row direction, the display driving method comprises steps of: respectively calculating a color component of each sub-pixel in the plurality of the first pixel units and a color component of each sub-pixel in the plurality of the second pixel units; and determining a sampling region of each sub-pixel, and determining a display brightness of the sub-pixel in accordance with the color components of sub-pixels, which is the same color as the sub-pixel and in pixel units covered by the sampling region of the sub-pixel, wherein the sampling region is a rhombic sampling region, and four vertexes of the rhombic sampling region are respectively midpoints of four lines in row and column directions connecting four central points of four sub-pixels, which are the same type as the sub-pixel, adjacent to the sub-pixel, in two columns adjacent to the sub-pixel.