In this study, the hydrophilic oligomer and cross-linking agent with high hydrophilicity and flexibility were added to increase the hydrophilicity and extensibility of the modified Nylon polymer, so as to improve the hydrophilicity of the modified Nylon polymer and the elongation of the fibers. Futher research the changes of fibers and fabrics under different environmental humidity. The experimental results show that the modified Nylon polymer have good water absorption ≥ 10%, the moisture -absorbing elongation of the modified Nylon fibers ≥ 12%, the porosity change ratio of fabric(dry and wet) ≥ 40%, and the air permeability change ≥ 20%.