A naked eye 3D display device is provided. The naked eye 3D display device includes a directional projection screen, a laser light source, a red monochromatic laser light source, a green monochromatic laser light source and a blue monochromatic laser light source. Lights emitted by the three monochromatic laser light sources emit incident light on the directional projection screen with nano-grating pixels at specific angles and specific positions, and the same emergent light fields are formed. The laser light source provides multi-perspective image pixels. The multi-perspective image pixels match a nano-grating pixel array on the directional projection screen. By a direct spatial modulation for the laser projection light, colorful 3D display is achieved. There is no crosstalk between various viewpoints. The naked eye 3D display device has no visual fatigue and has a low cost.