A high polymeric organosiloxane cationic emulsion composition comprising (A) a polydiorganosiloxane of formula: HO--[R.sub.2SiO].sub.n--H wherein R is an organic group and n is a number to give a viscosity of at least 300 Pa-s at 25.degree. C., (B) a cationic surfactant of formula: Q.sub.3(CH.sub.3)N.sup.+X.sup.-wherein Q is an organic group and X is halogen or carboxyl, and (C) water is fully stable. It is prepared by dispersing a corresponding organosiloxane and the cationic surfactant in water to form an emulsion, polymerizing in the presence of an alkali catalyst at 0-90.degree. C. for 10-150 hours, and neutralizing with an acidic compound.