The disclosure provides a three-dimensional (3D) display device including a pixel array and a grating. The pixel array includes a plurality of pixel columns, each of the plurality of pixel columns is inclined by an angle with respect to a direction in which an edge of the pixel array extends, and inclined angles of the pixel columns are substantially the same; each of the pixel columns is formed by arranging sub-pixels of three colors repeatedly in a fixed order, wherein dot pitches between any two adjacent sub-pixels in a same pixel column are substantially the same, and the sub-pixels in one of any two adjacent pixel columns in the plurality of pixel columns are staggered in turn with respect to respective sub-pixels in another pixel column of the two adjacent pixel columns and dot pitches between any two adjacent sub-pixels in the two adjacent pixel columns are substantially the same.