Burks went three for four with a two-run double in the first inning, a two-run homer in the third and a three-run shot in the seventh. Burks has 11 home runs, including four in three games since returning from the disabled list.
The Rockies have lost a season-high six consecutive games, while the Giants moved within one game of NL West-leading Arizona.
Kirk Rueter (7-3) gave up six hits and one walk in his first complete game since July 28. It was a complete turnaround from his last start against the Rockies, when he gave up five runs in one-third of an inning on April 22.
The Giants pounded Bobby Jones (3-7) for six runs and seven hits--five of them for extra bases--in four innings.
Singles by Bill Mueller and Barry Bonds set up Burks' three-run homer in the seventh against Curtis Leskanic. It was Burks' 15th career multi-homer game.