In this study, we assessed the effectiveness of acylase I from Aspergillus melleus in the treatment of polyamide (PA) fabric. The hydrolytic activity of acylase was evaluated by measuring the number of carboxylate ions released into the treatment liquid and the color strength (K/S value) of α-bromoacrylamide reactive-dyed fabrics. Since acylase hydrolyzed amide bonds in PA fabrics, the larger number of carboxylate ions were released into the treatment liquid and the number of ionic groups formed on the fabric surfaces was increased. The optimal conditions for the enzymatic treatment of PA fabric were determined to be pH 8.0 at 50℃ with a treatment time of 60 minutes. The hydrolysis products were formed on the acylase-treated fabric surface stably, as demonstrated by the results for wash fastness. The moisture regain and wettability of the fabric improved due to the newly generated ionic groups formed on the fabric surface by acylase hydrolysis.