Speckle-eliminating orthographic projection screen and preparation method thereof, and projection system

The invention discloses a speckle-eliminating orthographic projection screen and a preparation method thereof, and a projection system, a display surface of a screen body is set to be a random rough surface, and a probability density function P (z) of height z distribution of each position of the random rough surface accords with Gaussian distribution, so that when projection laser is projected to the random rough surface of the screen body, the random rough surface of the random rough surface is projected to the random rough surface of the screen body; the random rough surface is used for surface scattering of projection laser, inhibition of wavelength diversity and angle diversity on speckles is enhanced, independence of speckle patterns generated by two speckle inhibition modes of wavelength diversity and angle diversity is increased, the speckle inhibition effect is improved, the image quality of a laser projection screen is improved, and the image quality of the laser projection screen is improved. In ad