2, 4, 6-Trimethyl-2, 4, 6-tris (3', 3', 3'-trifluoropropyl) oyolotrisilozane, D₃^F, is synthesized by reaoting 3, 3, 3-trifluoropropyl magnesium ohloride with methyltri- methozysilane (1),whioh may simultaneously aot as reactant and as solvent in place of ether in Grignard reagent formation. The reaction product, 3, 3, 3-trifluoropro- pylmethyldimethogysilane (3),undergoes hydrolysis with HCl, and the hydrolysate is cracked and fractionated in the presence of KOH. D₃^F is formed in good yield and high purity suitable for the preparation of fluorosilioone elastomer directly. This method seems to be safe and convenient when it is compared with the industrial method of adding gaseous 3, 3, 3-trifluoropropene with methyldiohlorosilane under pressure in the presence of platinum catalyst.