Abstract: Particle(hereafter referred together as sand) can be used as the supporting material of 3D printing, which avoid the damage to the workpiece caused by removing the supporting in traditional 3D printing. For concluding the sand stacking law in the new FDM 3D printing technology, this paper designed the physical experiment to search the law of sand’s angle of repose by Plackett-Burman at first, in which the funnel aperture X₁, the funnel height X₂, the funnel horizontal moving speed X₃ and the glass sand size X₄ were selected as parameters. Secondly, the variation of sand’ accumulation degree under different funnel aperture was analysed by DEM simulation. It was found that the aperture of the hopper X₁ and the horizontal movingspeed of the hopper X₃ significantly affect the angle of repose, and the influence is negative. Besides, sand’s accumulation degree increases with the increase of funnel aperture. Therefore, in 3D printing supported by sand, increasing the funnel aperture, which inhibit the sand’s angle of repose and improve the sand accumulation, can improve the printing quality.