Matt Harrison (6-6) easily protected the early lead, giving up a run on seven hits with four strikeouts in seven innings.
Three of the first four batters scored in the Texas first off Mike Pelfrey (4-6). Ian Kinsler opened the inning with a double, moved to second on a sacrifice and then scored on Josh Hamilton's single. Beltre followed with his 13th homer of the season.
The Rangers produced a 13-hit attack that featured two-run homers by Michael Young in the seventh and Hamilton in the eighth.
Texas has won five of its last seven and the Mets have dropped five out of eight.