The Gunners kept the trophy they won against Hull City a year ago and earned Arsene Wenger a sixth triumph.
It's the 12th time the team have won the world's most famous cup competition.
Arsenal's victory was never in doubt as they dominated with a magnificent display.
Five minutes before half-time their control was rewarded with a goal from Theo Walcott.
Alexis Sanchez scored again shortly after with an amazing goal - a swerving, dipping 25-yard thunderbolt that flew high past startled Villa keeper Shay Given.
Per Mertesacker took advantage of a lack of marking to head the third.
And substitute Olivier Giroud's fourth in the final moments completed their stunning victory.
Arsenal have become the most successful club in FA Cup history after beating Aston Villa 4-0 at Wembley.