The youngster was out of contract at Portman Road and the Championship club will be owed compensation after they offered him a new deal, but could not agree terms.
Benyu was reportedly attracting interest from Premier League clubs, but has chosen to move to Brendan Rodgers’ treble-winners.
“I’m looking forward to meeting up with my new Celtic team-mates. I know there’s a lot of hard work ahead of me, but I am ready for this.
Benyu was on loan at Aldershot last year, where he made 21 appearances and scored five goals.