The present invention is the preparation of alpha-chloro-hydrocarbon siloxane. The alpha-chloro-hydrocarbon siloxane is prepared with alpha-chloro-hydrocarbon silane as material and nitrous compound as proton absorbent and through no-solvent liquid phase alcoholysis reaction. The reactant consists of alpha-chloro-hydrocarbon siloxane, alcohol and proteon absorbent in the molar ratio of 1 to 3.0-3.6 to 3-4.5, and the reaction has reaction temperature 10-60 deg.c, reaction time 1-2 hr and balance time 2 hr. The alpha-chloro-hydrocarbon siloxane product is obtained while using urea as HCl absorbent to protect active chlorine atom in alpha position. The present invention has alpha-chloro-hydrocarbon siloxane yield greater than 98% and hydrochloric acid content less than 4 ppm. |