The gas acceleration test was conducted to identify the deterioration of Korean traditional textiles caused by NO2. Total 20 specimens were prepared using 4 different materials (silk, cotton, ramie, hemp) after dyeing with 5 colors (undyed, red, yellow, blue, black). The specimens were exposed to 0.01, 0.1, 1, 10, 100, and 1000 ppm NO2 gas in the test chamber at 20℃, 50% RH for 1 day. Optical, chemical, and physical evaluation was carried out after the exposure. In the case of Korean traditional textile, color difference increased at 1 ppm/day, NO3- concentration, carbonyl and C-NO2 functional group increased while pH decreased at 10 ppm/day and tensile strength weakened at 100 ppm/day. when it comes to undyed textile, alteration of color difference on silk and hemp cloth, NO3- concentration and tensile strength on hemp cloth was remarkable. In addition, color difference on blue and yellow textile, NO3- concentration increase of yellow textile and tensile strength decrease of hemp cloth & ramie cloth were significant. The results suggest that critical NO2 concentration of optical, chemical, and physical damage on Korean traditional textiles are 1ppm/day, 10 ppm/day, 100 ppm/day respectively.