The invention provides a flow guide plate for a pesticide applying machine special for cotton. The flow guide plate comprises a flow guide plate body, wherein the flow guide plate body comprises an arc-shaped partition, an S-shaped partition and a plurality of fins; the fins are vertically connected with the arc-shaped partition and the S-shaped partition; the fins, the arc-shaped partition and the S-shaped partition are connected to form a plurality of channels. The flow guide plate for the pesticide applying machine special for the cotton, provided by the invention, can change the direction of high-pressure airflow, and the high-pressure airflow is blown out of a wind barrel, so that the wind speed in the effective pesticide applying area range is basically uniform in the fogdrop dispersing process and the fogdrops can penetrate through dense branches and leaves of the cotton well.