The invention relates to a whole row clamping device of a mechanical plug seedling grafting machine, belonging to agricultural grafting equipment; N grafting clamp cylinders are fixedly arranged on acylinder frame; a clamp opening is arranged at the bottom of the grafting clamp cylinder, and a guide rail is arranged at the side of the cylinder frame; a double-rod cylinder is arranged on the guiderail; a cylinder return pressure spring is arranged between a spring seat plate and the double-rod cylinder; one side of the guide rail is provided with a servo motor with an eccentric wheel, and theeccentric wheel is contact with the double-rod cylinder; a clip taking and feeding assembly is arranged at the lower portion of the side of N grafting clamp cylinders, and is connected with the double-rod cylinder; the clip taking and feeding assembly is composed of a roller, a positioning locking jaw, a locking jaw pressure spring, a locking boss, a fixed clamping jaw, a fixed jaw seat body, a jaw seat return pressure spring, a movable clamping jaw and a movable jaw seat body; the whole row clamping device of the mechanical plug seedling grafting machine has the advantages of being reasonable and compact in structure, high in automation degree, reliable in operation, good in clamping effect and high in clamping efficiency.