Phenomena of Al segregation at grain boundaries of Cu-Al-Be-X alloys( X= B, Cr and Ti) have been investigated. It has been discovered that after hot rolling and heat treatment of 850 degreesC air-cooling Cu-Al-Be-B alloy presents positive Al segregation, Cu-Al-Be-Cr alloy presents negative Al segregation, but Cu-Al-Be-Ti alloy does not present Al segregation at grains boundaries. It is suggested that this might be caused by a non-equilibrium grain boundary segregation process.