They ended two strokes clear of the field at 24-under-par 264.
Kuchar, who was coming off a 1-3-1 week at the Presidents Cup, and Woodland were both playing this tournament for the first time. They were the first United States duo to win this title since 2000.
"For Gary and I to team up and win World Cup of Golf is great," said Kuchar in a television interview. "I think Gary was the best individual player in the field this week."
England's Ian Poulter and Justin Rose fired a nine-under 63 for the low round of the day. That helped them grab a share of second place at 22-under-par 266. Germany's Martin Kaymer and Alex Cejka posted a three-under 69 to share second with England.
Australia's Richard Green and Brendon Jones, who had at least a piece of the lead after the first two rounds, also shot 69 on Sunday to finish tied for fourth at minus-21 at Mission Hills Golf Club.
They were joined there by Ireland, Netherlands and Scotland. Graeme McDowell and Rory McIlroy led entering the final round, but managed just an even-par 72 for Ireland. Robert-Jan Derksen and Joost Luiten shot 68 for Netherlands, while Stephen Gallacher and Martin Laird fired a 66 for Scotland.
The teams played foursomes in the final round as they also did in round two. The first and third rounds were played as fourballs.
After a birdie on the first, Kuchar rolled in a birdie putt at the second to give the Americans their first lead.
"Kuch's up and down on the last hole yesterday gave us a lot of momentum, and that carried into today as we birdied the first two holes," Woodland said in a TV interview.
They parred the next three holes and were joined in the lead by Ireland and Australia. After Ireland birdied the fifth to move to 22-under, the U.S. birdied No. 6 to join them there.
Kuchar drained a 12-footer for birdie on the seventh to give the U.S. the lead once again. They remained alone atop the leaderboard the rest of the way.
After tripping to a bogey on No. 11, the U.S. still held a one-stroke lead. Woodland hit a nice bunker shot inside three feet at 12 and Kuchar knocked that putt in for birdie.
On the 13th, Woodland poured in a birdie effort from about 25 feet out to move the Americans to 24-under. They parred the final five holes, which was enough for the two-stroke win.
Ireland fell off the pace with bogeys at 12 and 15.
England's stellar round got going with four birdies in a five-hole stretch from the second. After birdies on 11 and 12, they dropped a stroke on the 14th. However, England bounced back with a birdie on 15, and eagle at the driveable 16th and a birdie at the last to share second.
Germany had a steady round with three birdies and 15 pars to end alongside England.
NOTES: Tiger Woods and David Duval were the last U.S. team to win this crown...Francesco and Edoardo Molinari, the 2009 champions from Italy, carded a two-over 74 Sunday to end in alone in 17th at minus-14.