A directional optical waveguide, comprising: a time division multiplexing unit, and N layers of stacked optical waveguides (10, 111, 121,...1N1) with a same light-emitting direction, a light-emitting surface of each layer of the optical waveguide being provided with a pixel-type grating (10A, 112, 122,...1N2), and N being an integer greater than or equal to 2; characterized in that, the time division multiplexing unit is configured to control a light source, according to a stacking order of the N layers of optical waveguides (10, 111, 121,...1N1) within each frame video stream cycle, to enable the N layers of optical waveguides (10, 111, 121,...1N1) to introduce a source light ray into the corresponding pixel-type grating (10A, 112, 122,...1N2) during a corresponding frame video period, the each frame video stream cycle comprises N frame video periods in a one-to-one correspondence with the N layers of optical waveguides (10, 111, 121,...1N1); the pixel-type grating (10A, 112, 122,...1N2) of each layer of the optical waveguide (10, 111, 121,...1N1) is configured to: diffract source light ray that is introduced into the pixel-type grating (10A, 112, 122,...1N2) to form a plurality of first-order diffraction light rays in a one-to-one correspondence with display pixels; N layers of stacked optical waveguides (10, 111, 121,...1N1) are configured such that the plurality of first-order diffraction light rays are incident on an optical waveguide opposite to a light-emitting surface of the optical waveguide in which the pixel-type grating (10A, 112, 122,...1N2) is located; wherein a pixel-type grating (10A, 112, 122,...1N2) corresponding to each layer of optical waveguides (10, 111, 121,...1N1) comprises k gratings in a one-to-one correspondence with k display pixels; gratings corresponding to a same display pixel in adjacent two layers of optical waveguides (10, 111, 121,...1N1) have a same grating cycle and have different grating phases, such that when the source light rays introduced by each layer of the optical waveguides are diffracted for different times, after the source light rays introduced by each layer of the optical waveguides (10, 111, 121,...1N1) are diffracted for corresponding times, diffraction angles of the plurality of first-order diffraction light rays that are formed are different, and diffraction azimuth angles of the plurality of first-order diffraction light rays that are formed are different. a time division multiplexing unit, and N layers of stacked optical waveguides (10, 111, 121,...1N1) with a same light-emitting direction, a light-emitting surface of each layer of the optical waveguide being provided with a pixel-type grating (10A, 112, 122,...1N2), and N being an integer greater than or equal to 2; characterized in that, the time division multiplexing unit is configured to control a light source, according to a stacking order of the N layers of optical waveguides (10, 111, 121,...1N1) within each frame video stream cycle, to enable the N layers of optical waveguides (10, 111, 121,...1N1) to introduce a source light ray into the corresponding pixel-type grating (10A, 112, 122,...1N2) during a corresponding frame video period, the each frame video stream cycle comprises N frame video periods in a one-to-one correspondence with the N layers of optical waveguides (10, 111, 121,...1N1); the pixel-type grating (10A, 112, 122,...1N2) of each layer of the optical waveguide (10, 111, 121,...1N1) is configured to: diffract source light ray that is introduced into the pixel-type grating (10A, 112, 122,...1N2) to form a plurality of first-order diffraction light rays in a one-to-one correspondence with display pixels; N layers of stacked optical waveguides (10, 111, 121,...1N1) are configured such that the plurality of first-order diffraction light rays are incident on an optical waveguide opposite to a light-emitting surface of the optical waveguide in which the pixel-type grating (10A, 112, 122,...1N2) is located; wherein a pixel-type grating (10A, 112, 122,...1N2) corresponding to each layer of optical waveguides (10, 111, 121,...1N1) comprises k gratings in a one-to-one correspondence with k display pixels; gratings corresponding to a same display pixel in adjacent two layers of optical waveguides (10, 111, 121,...1N1) have a same grating cycle and have different grating phases, such that when the source light rays introduced by each layer of the optical waveguides are diffracted for different times, after the source light rays introduced by each layer of the optical waveguides (10, 111, 121,...1N1) are diffracted for corresponding times, diffraction angles of the plurality of first-order diffraction light rays that are formed are different, and diffraction azimuth angles of the plurality of first-order diffraction light rays that are formed are different.