The invention discloses a mechanical arm, the structure of which includes a gripper, a support arm, a swing cylinder, a telescopic rod, and a fixed platform. The support arm is hinged to the gripper, the support arm is fixed above the swing cylinder, and the swing cylinder is integrated with the fixation platform. The telescopic rod is located above the swing cylinder, and the gripper is equipped with a connecting rod, a fixing mechanism, and a force rod. Through the fixing mechanism on the gripper, the cylindrical object is more stable during the handling process, and it is effective for controlling the power rod to the limit block. Push to make the limit block move on the moving groove. Since the transmission rod penetrates through the rotation block and the limit block is limited and engaged, the rotation block is fixed. Since the fixing mechanism is distributed on the handle in an isosceles triangle ring, According to the principle that the triangle is more stable, a more stable effect is achieved. The compression mechanism on the pressure block compresses the cylindrical object, making the left side of the rubber block into a sealed state, and the pressure becomes smaller, and then the force of the compression block plus the suction makes it Cylindrical objects are stronger.