The invention relates to a double-layer-stretching three-dimensional grating and a manufacturing method of the grating. At present, all grating structures are in a planar shape, soil can be difficultly restrained, and the tensile strength of the grating cannot be fully achieved. The double-layer-stretching three-dimensional grating comprises double layers of longitudinal ribs and double layers of transverse ribs, wherein the longitudinal ribs and the transverse ribs are arranged in a parallel and perpendicular latticed manner; the longitudinal ribs and the transverse ribs are crossed to form pitch points, and the upper and lower layers of corresponding pitch points are connected together through vertical columnar bodies; the longitudinal ribs and the transverse ribs of the double-layer-stretching three-dimensional grating are stretched to form the double-layer-stretching three-dimensional grating which is stretched in double ways; the longitudinal ribs or the transverse ribs of the double-layer-stretching three-dimensional grating are stretched to form the double-layer-stretching three-dimensional grating which is stretched in the single way; the grating is a polymer plate with a certain hole array through injection molding or extrusion molding, and the polymer plate is subject to single-way stretching or longitudinal and transverse double-way stretching to form the double-layer three-dimensional grating; and more soil can be better wrapped and restrained, the soil is subject to geo-grid reinforcement, and the grating is obviously improved.