To obtain a liquid cation sizing agent composition having good absorbing property to clothes and good slipperiness to iron by blending a water- dispersible cationic sizing agent base with an aqueous dispersion of dimethylpolysiloxane.

A liquid crystal of a water-dispersible quaternary ammonium salt type cationic surfactant such as octadecyltrimethylammonium chloride is uniformly mixed with dimethylpolysiloxane at (5/95) to (50/50) weight ratio to prepare an aqueous dispersion. A water-dispersible cationic sizing agent base obtained by carrying out emulsion copolymerization of a lower fatty acid vinyl ester such as vinyl acetate with a cationic monomer such as 2-hydroxy-3- methacryloxypropyltrimethyl ammonium salt is mixed with the aqueous dispersion of dimethylpolysiloxane so that a weight ratio of the sizing agent base to dimethylpolysiloxane becomes (100/1) to (30/1) to provide the objective liquid cationic sizing agent composition.