The invention relates to the field of stacking machines, in particular to a pulley type stacking mechanical arm. The pulley type stacking mechanical arm comprises a base plate, a base, a support, a supporting column, a hydraulic arm, a movable arm, a pulley, a balance block and a pull rope. The base comprises a fixed base body arranged on the base plate and a rotary base body arranged on the fixed base body. The support is fixed to the base. The supporting column is vertically fixed to the rotary base body. The two ends of the hydraulic arm are hinged to the supporting column and the movable arm correspondingly. The pulley comprises an active rolling wheel and a fixed pulley body, the active rolling wheel and the fixed pulley body are arranged on the support, and the side face of the active rolling wheel is connected with a motor. One end of the pull rope is fixed to the other end of the movable arm, the middle portion of the pull rope winds across the fixed pulley body, and the other end of the pull rope is wound on the active rolling wheel by a plurality of circles. The balance block is connected with the other end of the pull rope and arranged in a suspended mode. According to the pulley type stacking mechanical arm, the rope and the pulley are used for force transmission, and the stress difference between the two ends of the rope is made smaller so that the output torque of the driving motor can be smaller when the mechanical arm moves, and the mechanical arm can save more energy.