A kind of uniformly-side-glowing optical fiber is designed and studied, which is obtained by scattering points graved on the plastic optical fiber (POF) by laser marking. This new fiber can be used as a directional backlight source for the autostereoscopic display. The model for a uniform side-glowing POF with laser marking engraved concave scattering points is established and used to derive the formula for calculating the scattering point coordinates. With the designed concave scattering point parameters, the model of side-glowing plastic optical fiber is established by the SolidWorks software, and the light ray tracing simulation is carried out based on the TracePro software. The results show that the tiny length semicircular angle change of scattering points, used for the characterization of depth and horizontal length of concave scattering points, has a large impact on the luminance uniformity. In contrast, the tiny axial width change of concave scattering points has a little impact on the side-glowing luminance uniformity. When the parameters are optimized, one can get the POF radius of R=0.25 mm, the concave scattering point width of d=0.15 mm, the scattering point length semicircular angle of θ=15°, the POF length of L=600 mm and the POF side-glowing luminance uniformity of 87.5% obtained by the TracePro simulation. According to the optimized design parameters, laser marking is used for graving scattering points on the POF surface and the obtained side-glowing luminance uniformity of single POF is 80.90%. Furthermore, a luminescence uniformity of 88.91% can be realized if the surface light source is composed of 100 side-glowing POFs. The experimental results show that the proposed design method and the fabricated POF surface light sources can meet the requirements of the directional backlight source design for 3D autostereoscopic display.