It makes the middleweight world champion the highest paid sportsperson in the world, according to his promoter Oscar De La Hoya.
Alarez, 28, has agreed the five-year-deal with sports streaming service DAZN.
It will offer fans a monthly subscription service to watch the fights rather than having to pay hefty pay-per-view fees.
The Mexican's last fight - a controversial win against Gennady Golovkin - cost $84.95 in the US.
Alvarez has a
huge following in America, especially among the large Spanish-speaking community.
Promoter De La Hoya told ESPN: "Canelo is the highest-paid athlete in the world. He's extremely happy."
The reported value of the deal would top the previous most-valuable contract - the $325m 13-year deal of baseball star Giancarlo Stanton in 2014.
Alvarez steps up to super-middleweight to fight Britain's Rocky Fielding in New York on 15 December - his first fight under the DAZN deal.