The victory eased some of the pain of a 2-1 loss to Australia last week that had left the three-time ASEAN champions in need of vital points if they are to go to Brazil.
"I'm very impressed with the match today. It's because of our hard work after the match with Australia," said Thailand coach Winfried Schafer. "We have three points today but we still have a tough job ahead playing Saudi Arabia. We have to keep working hard."
Sompong Soleb blasted the ball past Omani goalkeeper Ali Al Habsi, of English side Wigan Athletic, in the 35th minute while Muang Thong United's Teerasil Dangda outran the defence to ease the ball into the net six minutes later.
An own goal by Rashid Al Farsi in injury time rounded off a poor performance by Oman, who have a tough road ahead if they are to advance to Asia's final qualifying stages, after a goalless draw against Saudi Arabia last week.
The solid performance helped Thailand avenge their defeat to Oman in the same qualifying round for the 2010 FIFA World Cup. Thailand's next test comes when they host Saudi Arabia on 11 October, when Oman face Australia.