The invention discloses a transverse pushing feeding device and method for a grate cooler and belongs to the field of grate coolers. The transverse pushing feeding device comprises a plurality of sets of material pushing units which are located on a grate cooler grate bed and closely arranged in the material flow direction. Each set of material pushing unit comprises a pushing mechanism and a plurality of material pushing mechanisms arranged on the pushing mechanism. Each pushing mechanism is used for driving the corresponding material pushing mechanisms to move back and forth on the grate bed in the direction perpendicular to the material flow direction. The material pushing mechanisms have the length direction extending on the plane of the grate bed, and an included angle of 45-60 degrees is formed between the length direction and the material flow direction. According to the transverse pushing feeding method, the phase difference of reciprocating motion of the adjacent two sets of material pushing units is larger than 0 degree and smaller than or equal to 180 degrees. According to the transverse pushing feeding device and method for the grate cooler, the condition of a material layer is mainly and initiatively changed, and thus the material layer and cooling equipment can conduct energy distribution more reasonably; balanced distribution of cooling air is also more beneficial through the change of the material layer, and cooling air adjusting through a mechanical method is not needed; and in addition, the influence of the balanced material layer on the cooling effect is also more obvious.