Abstract: For enhancing the effect of liquid ammonia and sodium hydroxide swelling treatment of linen fabric,infrared spectra,crystalline structure,moisture regain,dyeing properties and mechanical properties of linen fabrics treated by different swelling processes were measured.It is found that no significant changes exhibit in the chemical structure of the linen fibers treated by different swelling processes.However,crystallinity was decreased not only by the NaOH treatment but also by the NH_3 treatment,especially by the latter.Moisture regain and equilibrium dyeing rate of the fabric treated by NaOH/NH_3 were increased 19.08% and 12.61% respectively.NaOH/NH_3 treated linen fabric has better cantilever bending stiffness,crease recovery,tensile strength and other mechanical properties than the mercerized linen fabric.