A pneumatic distinguishing mistake-proofing mechanism belongs to the field of automobile manufacturing, and the mistake-proofing mechanism comprises a main air inlet, a vehicle model 1 air connection, a vehicle model 2 air connection, a vehicle model 1 air outlet, a vehicle model 2 air outlet and a roller; a
mechanical valve is arranged between the main air inlet and the roller, the
mechanical valve is actuated between the vehicle model 1 air connection and the vehicle model 2 air connection, when a workpiece presses the roller, the
mechanical valve connects the main air inlet and the vehicle model 1 air connection to ventilate, when the workpiece does not press the roller, the mechanical valve connects the main air inlet and the vehicle model 2 air connection to ventilate. The roller of the mechanical valve is used as an identifier, the slight difference of the same kind of different models of parts can be identified, the different air connections and air outlets are connected through the roller, and then the differentiation of different models of parts is realized, and then subsequent related actions are carried out.