Al-intermetallic eutectic composites are typical structural materials because of their lightweight and high strength comparable to steel. Al-Cu alloys with a high volume fraction of nanoscale intermetallic precipitates (Al2Cu) exhibit enhanced ductility and strength at room temperature while improved strength at elevated temperatures. Understanding fundamental character and motion of dislocations in Al2Cu is essential for advancing microstructural design of Al-intermetallic eutectic composites. Using atomistic simulations, we studied seven slip systems in Al2Cu. Three edge dislocations with Burgers vector <001> on glide planes (110), (010), and (310), show an extended core, and glide at room temperature. Other four edge dislocations and three screw dislocations with Burgers vectors <001>, <110>, and 1/2<111> show a condensed core, and don’t glide at room temperature. Furthermore, Interaction of dislocation dipole results the climb of the extended-core dislocation at moderate temperatures. Interface structures of Al-Al2Cu and their roles in mechanical deformation are studied and discussed.