The attacking midfielder, 22, joined the Dons on loan in January and scored seven goals in 15 games, including five in his last five outings.
With Jonny Hayes heading the other way for a reported £1.3m fee, retaining Christie, along with manager Derek McInnes, provides some solace for fans.
Niall McGinn, Ryan Jack, Peter Pawlett and Ash Taylor have also left the Dons.
They have already signed midfielder Greg Tansey from Inverness, with other replacements set to follow.
Christie signed for Celtic from Inverness Caledonian Thistle in a deal worth around £500,000 in September 2015 but immediately rejoined the Highlanders on loan until January 2016.
He started last season back in Glasgow but was restricted to just seven outings for the champions until the end of the year before joining Aberdeen on loan.
Ryan Christie will return to Aberdeen on a season-long loan deal from Celtic for the forthcoming campaign.