The invention discloses a pop can flattening machine. The pop can flattening machine comprises a support base, a positioning mechanism and a flattening mechanism; the positioning mechanism and the flattening mechanism are both arranged on the upper end surface of the support base; the flattening mechanism is positioned above the positioning mechanism; the positioning mechanism comprises multiple annular rings; each ring is detachably mounted on the upper end surface of the support base through a first support rod; the center axes of the multiple rings are perpendicular to the upper end surfaceof the base; the flattening mechanism comprises a stand column; a vertical slide rail is arranged on the stand column; a positioning slide block slidingly matched with the vertical slide rail is mounted on the vertical slide rail; a slide block driving cylinder for driving the positioning slide block to slide along the vertical slide rail is mounted on the stand column; pressing block modules asmany as the rings are mounted on the positioning slide block; and one ring is arranged rightly below one pressing block module. The pop can flattening machine is high in working efficiency, and savesa lot of manpower.