Abbiati spent 15 seasons as a Milan player before retiring at the end of the 2015-16 campaign, winning three Serie A titles and the Champions League in the 2002-03 campaign.
In a statement, Milan explained Abbiati will act as a link between Vincenzo Montella's team and the board, with Chinese group Sino-Europe Sports having completed a takeover in April.
"He will report directly to the club's sporting and technical director Massimiliano Mirabelli and will be the liaison between the team and the club," Milan said.
Preparations for the new season are well under way at Milan, with Montella having signed a new contract and the club bringing in Andre Silva from Porto on Monday as their fourth signing of the close-season.
The forward joined centre-back Mateo Musacchio, midfielder Franck Kessie and left-back Ricardo Rodriguez in moving to San Siro and Abbiati says Milan have bold ambitions after the club's spending spree.
— AC Milan (@acmilan) June 14, 2017
"The Champions League has to be our goal for the season," Abbiati said.
"That has to be the launch point from which to start again. Last year they did good work and now we've started with a project to take us forward.
"We hope to do everything to reach fourth place."