A novel alpha-1 antitrypsin variant, a method of preparing the same, and use thereof are provided. The alpha-1 antitrypsin variant has excellent stability in the body and maintains an inhibitory effect on elastase activities because the blood half-life (t1/2) and the area under blood drug concentration vs. time curve (AUC) are remarkably increased by adding an N-glycosylation site in animal cells through amino acid mutation between 1st and 25th positions of the N-terminus of alpha-1 antitrypsin. Therefore, the alpha-1 antitrypsin variant can be useful in preventing or treating alpha-1 antitrypsin deficiency.