Microstructure　of　post-homogenization　is　significant　to　prevent　particle　stimulated　nucleation　of　recrystallization.　This　paper　investigated　microstructure　evolution　in　alloy　7050　during　cooling　from　homogenization.　Two　intermetallic　phases,　Al7Cu2Fe　and　Mg2Si　were　insoluble　during　homogenization.　Cooling　to　460　°C　and　400　°C　follow　by　quenching,　precipitates　nucleated　discontinuously　on　the　grain　boundaries,　no　precipitates　was　found　within　the　grains.　The　precipitates　were　found　near　the　grain　boundaries　when　quenching　from　350　°C,　and　precipitated　uniformly　within　the　center　of　the　grains　when　quenching　from　250　°C.　The　sizes　of　the　precipitates　increased　with　the　decreased　of　the　quenching　temperature.　Controlling　of　the　post-homogenization　microstructure　is　beneficial　to　prevent　particle　stimulated　nucleation　of　recrystallization.　©　(2014)　Trans　Tech　Publications,　Switzerland.