In order to improve dye uptime and wash fastness on dyeing of cotton fabrics with Amur cork tree, twitter ionic groups, acid groups, hydrophobic groups or cross linkage were introduced into cotton fabrics. Results obtained were as follows, 1 The optimum modification of cotton fabrics was carbosy methylation in the water solution containing 15% sodium chloroacetate and 15% sodium hydroxide and then introducing hydrophobic groups by treating in the solution containing $30mell$ DMSO and $3mell$ 2,4-TDI 2. Numbers of carbon, diisocyanate group than monoisocyanate group and aromatic compound than aliphatic compound in introduced hydrophobic groups were effective. 3. The dye uptake and wash fastness wore enhanced significantly by treating only with 2,4-TDI. 4. The wash fastness seems to correlate to the degree of swelling of the fabric during washing and also depend on the Interaction between dyes and acid groups as well as hydrophobic groups.