The invention discloses an accessory automatic adjustment method and device, and is applied to a carrying robot. The accessory automatic adjustment device is provided with a scanning distance measurement module, a computation module, a control module, an accessory support and an accessory installed on the accessory support; the accessory support and the accessory are each provided with a displacement sensor, output ports of the displacement sensors are connected with an input port of the control module, and the displacement sensors feed the accessory support height and the accessory transverse opening and closing size values back to the control module; the scanning distance measurement module scans an object to be loaded and obtains the position and appearance information of the object to be loaded; furthermore, the computation module determines the accessory transverse opening and closing position value and the accessory support height target position value; and the control module controls a transmission mechanism to move the accessory transverse opening and closing size and the accessory support height to the target position values. The carrying robot can identify the object to be loaded and automatically adjust the accessory on warehousing and storage activity sites, and therefore the object to be loaded can be correctly loaded to the carrying robot.