The utility model provides an anti-retraction mechanism for a three-plate mold elastic plate. The anti-retraction mechanism comprises a deflector rod of which the upper end is fixed to a fixed template of a movable mold, a pull rod of which the lower end is fixed to a compound plate of the elastic plate, a shifting block, a shifting block base which is fixed to a movable template of the elastic plate, and an elastic piece, wherein one side face of the lower end of the deflector rod is an oblique plane; a concave buckle is arranged on one side face of the upper end of the pull rod; a groove matched with the lower end of the deflector rod is formed in the upper end of the shifting block, and an elastic piece assembly hole is formed in one side face of the deflector rod; a horizontal-guiding shifting block guide groove, a vertical-guiding deflector rod guide groove and a pull rod guide groove are formed in the shifting block base; the shifting block guide groove is communicated with the pull rod guide groove and the deflector rod guide groove; the upper end of the pull rod is arranged in the pull rod guide groove; the shifting block is arranged in the shifting block guide groove; the elastic piece is arranged in the elastic piece assembly hole, and is pressed against the shifting block guide groove; one end of the shifting block can be clamped into the concave buckle of the pull rod; the lower end of the pull rod passes through the deflector rod guide groove, and is matched with the groove. By adopting the anti-retraction mechanism, the elastic plate can be locked completely, and is high in stability. The anti-retraction mechanism is simple in structure, low in manufacturing cost, and convenient to repair.