The invention discloses an auxiliary mechanical arm used for live working and a robot. The auxiliary mechanical arm comprises a base, a large arm, a front arm and a gripper. A hydraulic swing oil cylinder is arranged on the base and drives the large arm to rotate by 180 degrees in the horizontal plane. A pitching oil cylinder I driving the large arm to do pitching motion is hinged to the large arm. The front arm perpendicular to the tail end of the large arm is hinged to the tail end of the large arm. The front arm is driven by a pitching oil cylinder II to do pitching motion. The gripper is installed at the tail end of the front arm. The front arm is made of insulating material glass fiber reinforced plastic and can conduct direct live working. The auxiliary mechanical arm comprises the gripper which can be freely opened and closed and can freely conduct grasping.