The invention relates to a cross-correction mechanism for a diaphragm mounter. The cross-correction mechanism comprises a correction platform panel, wherein an upper bottom plate and a lower bottom plate are arranged below the correction platform panel, and a connecting rod mechanism is arranged between the upper bottom plate and the lower bottom plate. The cross-correction mechanism is characterized in that: a diaphragm placing table is arranged on the correction platform panel, and a correction positioning mechanism for adjusting the diaphragm placing table is respectively arranged at the four sides of the diaphragm placing table; the correction positioning mechanism comprises correction positioning blocks in four directions, positioning block mounting seats for installing the correction positioning blocks, and micro slide rails for guiding the positioning block mounting seats to slide. By the movement of the connecting rod mechanism and the slide rails, the vertical movements in four directions in a vertical plane are converted into four corresponding horizontal movements in a horizontal plane, movement points in a single direction just satisfy a mathematical model of a Pythagorean Theorem, and a movement mechanism is designed reasonably, does not easily bend or deform, and is simple to process, so the cross-correction mechanism is more accurate and rapid in cross alignment.