The 23-year-old winger joins from Blue Square Bet South side Havant & Waterlooville and begins manager Neal Ardley's preparations for next season.
The Kingsmeadow outfit become Arthur's ninth club and the ex-QPR and Northampton man is back in the Football League after a year out.
He told the club's official website: "I am delighted to sign for a club with a lot of passion because it has great supporters and a good history.
"I had a meeting with Neal at the training ground and he sold the club to me straight away with his ambitions. They matched my ambitions because of the players Neal wants to bring in and the good football he wants to play."
The Dons survived relegation by two points last term, meaning a busy summer is ahead for Ardley, who can see the raw potential of his latest recruit.
"We have watched Chris a lot during the last season and though he is not a high-profile signing, I am sure Wimbledon's fans will be excited by his talents," he said.
"He has got unbelievable pace, a great left foot and he can also fill in at left-back. I think we can develop Chris and turn him into a very good player.
"We moved quickly for Chris because we wanted to sign him as soon as the season ended. He had a great season at Havant and we believe he will fit in well to the dynamics of our team."
Artur appeared 38 times last season for Havant, scoring twice.