This study was conducted to examine the effects of chitosan on the changes in physicochemical characteristics and hardness during Kimchi fermentation. The Kimchi samples were stored for 8 days at $20{pm}l^{circ}C$. The results were as follows : The pH value was decreased in order of Kimchi treated with 0.05% of 5% chitosan solution(chitosan 0.05%), Kimchi treated with 0.025% of 5% chitosan solution(chitisan 0.025%), Kimchi treated with 0.01% of 5% chitosan solution(chitosan 0.01%) and control, and the total acidity was increased in the opposed order. Volatile acid was increased like the total acidity, it was decreased after 6 days during fermentation, reducing sugar contents of Kimchi samples were decreased gradually. The ascorbic acid contents of Kimchi were increased rapidly in the early stage of fermentation and decreased in the late stage. Properties of hardness of Kimchi measured instrumentally were higher in the Kimchi treated with chitosan than control throughout the fermentation period.