Proposed is a method for the finishing treatment of various kinds of fabric materials with an aminoalkyl-modified dimethylpolysiloxane to impart the fabric material with excellent softness and smoothness with less disadvantages of yellowing of the treated fabric material than in the prior art using similar aminoalkyl-modified dimethylpolysiloxanes. In the inventive method, the aminoalkyl-modified dimethylpolysiloxane is represented by the general formulaA--SiR.sub.2 --O--(--SiR.sub.2 --O--).sub.p --(--SiRQ--O--).sub.q --SiR.sub.2 --A,in which R is a monovalent hydrocarbon group having 1 to 20 carbon atoms, Q is an aminoalkyl group expressed by the general formula--R.sup.1 --(--NH--CH.sub.2 --CH.sub.2 --).sub.n --NH.sub.2,R.sup.1 being a divalent hydrocarbon group having 1 to 8 carbon atoms and the subscript n being 2 or 3, A is a hydroxyl group, R, OR or Q, the subscript p is an average number in the range from 5 to 2000 and the subscript q is 0 or an average number not exceeding 100 with the proviso that q is not 0 when the groups denoted by A in a molecule are each a hydroxyl group, R or OR, and having an amine equivalent in the range from 5000 to 100,000 g/mole.