Sublattice reversal of GaAs epitaxial layers in a GaAs/Ge/GaAs(001) crystal was investigated using X-ray standing waves. The crystal was fabricated so that the sublattices of GaAs epitaxial layers were spatially inverted to those of the GaAs(001) substrate with the help of Ge intermediate layers. To make sure of this spatial inversion, variation of GaKα and AsKα fluorescence yields was measured as a function of incident angle under 115 and 115 Bragg conditions. The analysis showed that the angular variation of the measured fluorescence yields agrees well with that of theoretical calculations based on the spatial inversion.