The invention provides a pneumatic cotton sample quick-packing finishing device and finishing method. The finishing method includes step a) of moving a working table to an initial working position; step b) of laying packaging paper in a sample former, and placing a cotton sample with a specified weight on the packaging paper; step c) of using a glue gun to perform gluing on the outer side of the packaging paper, and causing mechanical hands to be overturned towards the inside of the sample former respectively; step d) of moving the working table to a second working position, causing the mechanical hands to be separated from the packaging paper and turning the mechanical hands out from the inside of the sample former to be in place, and causing a lower pressing plate located at the second working position to be pressed into the sample former from the top of the sample former, to stick and close the packaging paper. According to the pneumatic cotton sample quick-packing finishing method,by split arrangement of the lower pressing plate and the mechanical hands, on the one hand, the overall structural arrangement can be facilitated; on the other hand, an action interval can also be formed between the mechanical hands and the lower pressing plate, it is ensured that the packaging paper has a certain forming time, the turning back of the packaging paper can be prevented when the mechanical hands are separated from the packaging paper, and the pressing-down operation of the lower pressing plate is facilitated.