The invention provides a mechanical arm control method and a manned mechanical armor. The method is applied to the manned mechanical armor. The manned mechanical armor comprises a mechanical arm, an exoskeleton, calculation equipment and a reminding unit. Angle sensors are arranged on the exoskeleton. A model of the manned mechanical armor is stored in the calculation equipment. The method comprises the steps that the joint angle values of joints of the exoskeleton are acquired through the at least one angle sensor, and the collected joint angle values are sent to the calculation equipment; the calculation equipment carries out motion analysis according to the received joint angle values and the model of the manned mechanical armor; and the calculation equipment controls the work state of the reminding unit and/or the work state of the mechanical arm according to the motion analysis result. Therefore, the problems about information feedback and safety of exoskeleton-based control over the mechanical arm of the manned mechanical armor are solved.