Pleated wool fabrics were prepared by the treatment with ethylenediamine (EDA) at $90^{circ}C$ for 30 min. The degree of set, tensile property and dyeing of the treated fabrics have been discussed in relation to the concentration of EDA in the treatment system. No significant decreases in tensile strength and elongation, and great increases of exhaustion of synthetic and natural dyes were observed. Pleat and flat set were successfully attained in a wide range of the concentration of EDA. Excellent dyeability and setability of the fabrics obtained were considered to be associated with the existence of new crosslink, $eta$-N-(2-aminoethyl)alanino-$eta$-aminoalanine and the pendant group, $eta$-N-(2-aminoethyl) aminoalanine produced by the reaction of EDA with dehydroalanine intermediate.