damages of cotton cloth and characteristics of fabroid degradation were studied by Chaetomium globosum and Aspergillus niger which presupposed as powerful erosive fungi to cellulose fiber by means of tensile strength. The results obtained are as follows: 1. the growth(rate) of fungi in malt extract agar was superior to potato agar for two weeks. 2. Chaetomium globosum showed mostly severe damage t the cotton cloth in malt extract agar media at pH 4.5. 3. Tensile strength was reduced with time by Aspergillus niger-coenzyme and Chaetomium globosum-coenzyme reaction. In comparison with Chaetomium globosum and Aspergillus niger, the former weaken tensile strength about 15.8% and the latter enfeebled 10.0% after 124 hours. 4. after 30 days the breeding of fungi in pH 4.5 malt extract agar media, critical damage of cotton cloth was observe, I. e., 92.4% damage by chaetomium globosum and 74.9% lose by aspergillus nige respectively.