It is known that the addition of small concentrations of Cu to Al-Mg-Si alloys promotes improvement of mechanical properties, but distribution of Cu concentration in this alloy has not been investigated in detail. In present work, we examined the distribution of Cu around the interface of the precipitates by the energy filtering transmission electron microscope (EFTEM) and energy dispersive spectroscopy (EDS) The bright contrast of Cu has been observed in the Cu-map (931 eV) around the Q' phase, as a result of the elemental mapping by EFTEM. The same result has been also obtained from EDS analysis.