The invention relates to a flow guiding and cooling device for automobile exhaust emission. The flow guiding and cooling device comprises a flow guiding pipe and a flow guiding box, wherein one end of the flow guiding pipe is connected with an automobile exhaust emission pipe; the other end of the flow guiding pipe is arranged in the flow guiding box; a plurality of diffusion holes are formed in the part, arranged in the flow guiding box, of the flow guiding pipe; the flow guiding box is of a square box structure; a plurality of flow guiding plates are arranged at the inner bottom of the flow guiding box; a flow guiding channel is formed between every two adjacent flow guiding plates; and vent holes are formed in the flow guiding box and communicate with the flow guiding channels. The flow guiding and cooling device provided by the invention is connected onto the automobile exhaust emission pipe; through the flow guiding function, automobile exhaust is guided into a flow guiding chamber, the guided automobile exhaust is diffused through a diffusion channel arranged on the flow guiding chamber, and then the diffused automobile exhaust is emitted into the atmosphere; through diffusion and emission in the flow guiding chamber, the emission flow area of the automobile exhaust is enlarged, the automobile exhaust flow rate is reduced, and then the purpose of cooling the automobile exhaust is fulfilled; and the flow guiding and cooling device is simple in structure and convenient to use; the problem that in the prior art, the automobile exhaust emission temperature is high can be well solved; and the impact of the automobile exhaust emission on the environment can be reduced.