Physicochemical characteristics of Kochujang based on hot-air dried the red pepper powders with different treatments, were investigated during 90 days fermentation to obtain information for the industrial production of Kochujang. The pH was decreased gradually during fermentation, and pH of the control Kochujang was consistently higher than those of others. The total acidity was increased linearly during fermentation, and Kochujang with 0.1% vitamin C was consistently higher than others. Reducing sugar contents of Kochujang was increased until 75 days but was decreased slightly thereafter, showing highest value for the control sample. Amino nitrogen contents was increased gradually until 75 days, showing highest value for Kochujang with mash-dried red pepper powder, but it was decreased remarkably thereafter The L and a values of Kochujang were increased, whereas b value was decreased during fermentation. L, and b values of Kochujang with mash-dried red pepper powder were higher than those of others, showing the more light and deep color than others. Appearance, taste and overall acceptability of Kochujang based on mash-dried red pepper powder were higher than others.