We present an approach for constructing a realistic structure model of inhomogeneous amorphous materials by combining angstrom-beam electron diffraction, synchrotron X-ray scattering, and simulation techniques. Local structure information obtainable by angstrom-beam electron diffraction is effective to choose a probable model from some possible models that satisfy a structure factor of X-ray scattering. We applied this approach to amorphous SiO and successfully constructed a realistic model including nanoscale Si and SiO₂-like regions together with abundant interfacial Si suboxides.