James, who grew up in nearby Akron, spent his first NBA seasons with the Cavaliers before leaving in July of 2010 for the Heat, his decision seen as a betrayal by the Cleveland supporters who had adored him.
The Cavaliers struggled through last season while the Heat, with James joined by fellow stars Dwyane Wade and Chris Bosh, reached the NBA Finals before losing to Dallas.
Miami won an emotional return game to Cleveland last season and dominated again this time with Wade adding 22 points and Bosh contributing 16 points and 12 rebounds as the Heat improved to 24-7 with a fifth consecutive victory.
James had said before the game that if he ever did decide to return to the Cavaliers, he hoped Cleveland fans would accept him, feelings that a scorned fan base indicated might not be reciprocated.
The Heat jumped ahead 9-0 and 21-2 on the way to a 35-14 lead after the first quarter, Wade scoring 11 points in the opening quarter while James and Mario Chalmers each added nine in the period. Chalmers finished with 14 points.
Miami stretched the lead to 63-38 at half-time and the Cavaliers never threatened in the second half.
Kyrie Irving led the Cavaliers, 11-17, with 17 points.