What are differences in Achilles'character in troy and iliod?

Achilles' most prominent traits in the Iliad are (first) resentment and hurt pride, after a favorite slave has been taken from him, and (later) anger and ferocity after his best friend has been killed in battle.

If you mean: "how is Achilles' character different in the movie Troy from how it is in the Iliad", the answer is that it isn't much different. But the Iliad only describes the events in the very last year of 10 years' siege of Troy and does not say much of all that happened in the 9 years before. In the movie, all Achilles' acts that are shown from the beginning of the war can be considered to have been made up by the writers of the movie. Oh yes: and in the movie Achilles gets into the wooden horse and only dies after the conquest of Troy, while in the Iliad he dies much earlier and his son gets into the wooden horse.