MediaCom previously won the business reportedly worth US$190 million in 2010.
The final pitch was between Starcom, MediaCom and Carat in early September.
SMG's Shanghai office will oversee the servicing of the account. The brands under AB InBev in China include Budweiser, Harbin, Sedrin, Da Xue, Jinlongquan, KK, Tangshan, Double Deer, and Wei Xue.
JWT and Isobar are currently responsible for creative and digital duties for the client.
The media review in the mainland is part of a global process that involves Latin America and key European markets. Starcom already handles the media business in the U.S.