Provided are a method of preparing a metal oxide-silica composite aerogel, which includes preparing metal oxide-silica composite precipitates by adding a metal salt solution to a silicate solution and performing a reaction, and washing the metal oxide-silica composite precipitates with a washing solvent having a surface tension at 20±5° C. of 30 mN/m or less and drying the washed metal oxide-silica composite precipitates, and a metal oxide-silica composite aerogel having increased specific surface area and pore properties as well as tap density, which is significantly reduced by a maximum of 78.6% in comparison to a composite aerogel prepared by using water as a typical washing solvent, prepared by the method.