The object of the invention is a method for preparing silanes of the general formula (1) RaHbSiCl4−a−b (1), wherein mixtures of silanes of the general formulas (2) and (3) RcSiCl4−c (2), RdHeSiCl4−d−e, where R indicates an alkyl radical with 1 to 6 carbon atoms, a indicates the values 1, 2 or 3, b indicates the values 0 or 1, c indicates the values 1, 2, 3 or 4, d indicates the values 0, 1 or 2 and e indicates the values 0, 1 or 2, are reacted in the presence of an aluminum oxide catalyst comprising 1 to 10 parts by weight of aluminum chloride and 0.5 to 10 parts by weight of a metal oxide selected from magnesium oxide, copper oxide, zinc oxide and mixtures thereof to 100 parts by weight of aluminum oxide.