A robot arm processing system includes a robot arm, a processing module, and a control module. The robot arm is for providing a mechanical holding force. The processing module is disposed on the robot arm to process a workpiece. The control module is connected to the robot arm or the processing module. The control module outputs an anti-vibration signal according to the reaction force of the workpiece or the displacement of the robot arm to counteract the reaction force of the workpiece or the displacement of the robot arm.