The intensity of the N K edge in electron energy-loss spectra from a GaN thin film shows a pronounced difference when the orientation of the film approaches the (0002) and (000-2) Bragg reflections, along the polar direction. This experimental result can be interpreted by the effect associated with interference between the Bloch waves of the incident electron in the GaN crystal. The theoretical calculations indicate that, at the Bragg condition of g=0002 along the Ga–N bond direction, the thickness-averaged electron current density on the N atom plane is much higher than that at g=0002̄, with a maximum as the specimen thickness is about 0.4ξ0002 (the two-beam extinction distance). The delocalization effect on the experimental spectra is also discussed.