Ventilative car seat back

A ventilative car seat back of the present invention includes a main body, at least one air channel, plural air holes, and a deflector. The main body has a reclining surface, two side surfaces and a first connecting portion. One of the side surfaces is formed with at least one inlet, and the first connecting portion is located at the side surface which is formed with the inlet. The air channel is formed on the main body and communicates with the inlet. The air holes are formed on the reclining surface and communicate with the air channel. The deflector has a second connecting portion. The second connecting portion is connected to the first connecting portion. Thereby, the ventilative car seat back of the present invention provides better ventilation so that a user doesn't feel hot and stuffy when reclining on the seat back.