The invention relates to an apparatus and a method for concentrating ethanol through ultrasonic atomization. The apparatus provided by the invention comprises an ultrasonic atomization tank provided with an ultrasonic atomizer, a fog-like substance agglutination device and a collector, wherein the fog-like substance agglutination device is composed of a drum, a piston carrying out reciprocating motion in the drum and a spray system, the piston separates the drum into a left compression cylinder and a right compression cylinder, the two compression cylinders alternately carry out compression and agglutination of a fog-like substance, a material inlet and a material outlet are respectively arranged above and below a position in front of a stop point position of the piston in the two compression cylinders, nozzles are mounted on outer walls of the two cylinder, and a pump providing power to the nozzles is connected with the nozzles through pipelines. The method for concentrating ethanol provided by the invention employs the apparatus. Compared to the prior art, the invention has the following advantages: recovery efficiency of the fog-like substance after ultrasonic atomization is high, and good economical efficiency is obtained.