The invention discloses a height-adjustable stacking mechanical arm comprising a base, a lifting mechanism, an angle regulation mechanism and a clamping mechanism. Universal wheels are arranged at thelower end of the base. A parking cylinder is arranged at the upper end of the base. A parking fixed block is installed at the telescopic end of the parking cylinder. The lifting mechanism comprises arectangular shell, a lifting hydraulic cylinder, a first lifting push plate, a guide sleeve, a guide rod and a second lifting push plate. The angle regulation mechanism comprises a hydraulic rotationoil cylinder, a rotation base, a supporting arm, a first pitching arm, a first rotating shaft, a first bearing, a first pitching regulation hydraulic cylinder, a second rotating shaft, a second pitching arm, a second bearing, a regulation lever, a lever support, a second pitching regulation hydraulic cylinder, a rotation shell, a stepping motor, a rotation bearing, a drum and a turning plate. Theclamping mechanism comprises a clamping shell, a two-way cylinder and a hinge plate. Multiple vacuum suction cups are arranged at the lower end of the clamping shell. The height-adjustable stacking mechanical arm has the beneficial effects of being simple in structure and high in practicability.