After-treatment mixing device, after-treatment system and vehicle

The embodiment of the invention provides an after-treatment mixing device, an after-treatment system and a vehicle, the after-treatment mixing device comprises an outer pipe, an air inlet plate and a spiral plate, wherein a first air inlet is formed in the air inlet plate, a second air inlet is formed in the side wall of the outer pipe, and the spiral plate is wound into a spiral structure; a third gas inlet is formed between the third side and the fourth side, first gas entering from the first gas inlet and second gas entering from the second gas inlet can be mixed at the third gas inlet, and the mixed gas enters the spiral structure from the third gas inlet, so that a circulation path of the mixed gas can be prolonged, the gas mixing is more uniform, and the spiral structure can also save the length of the outer pipe, reduce the temperature loss of ammonia gas, improve the utilization rate of urea and improve the economical efficiency of the after-treatment system under the condition of prolonging a circula