The 51-year-old golfer from Chiang Mai pipped Thaworn Wiratchant with a 20-under 196 to grab the winner’s prize money of 120,000 baht.
Thaworn, 55, got 80,000 baht for finishing runner-up with a 19-under 197.
Prayad Marksaeng was third with a 12-under 204 while Rangsan Raksomjit and Thammanoon Sriroj were tied for fourth with a nine-under 207.
It was Udorn’s first tournament win this year and his seventh on the Thai Senior Tour.
Udorn said he was very happy to win because it was always close and exciting. He added that he was lucky to get off to a great start. Even though he slackened later, birdies in the last two holes took him clear of the field.