Is aniken skywalker the same actor in all 3 movies?

No, Anakin Skywalker is played by different actors in the Star Wars prequel trilogy (Episodes I-III):

* Episode I: The Phantom Menace (1999): Jake Lloyd

* Episode II: Attack of the Clones (2002): Hayden Christensen

* Episode III: Revenge of the Sith (2005): Hayden Christensen

Hayden Christensen plays Anakin throughout the rest of the trilogy, while Jake Lloyd was only in Episode I.