PURPOSE: To obtain the titled compound in high conversion of metallic silicon and selectivity of trialkoxysilane, in high yield, by adding an organic halide to a reaction system in the reaction of metallic silicon powder with alcohols in the presence of copper catalyst.

CONSTITUTION: A trialkoxysilane is produced by reacting metallic silicon powder with alcohols (preferably lower alkyl alcohol) in a reaction solvent in the presence of copper catalyst. In the above process, the reaction system is added with an organic halide (preferably alkyl halide, alkenyl halide or aryl halide). The amount of the halide is preferably 0.001W0.5mol. per 1mol. of the alcohols.