Loar carded a 19-under-par 269 on the par-72, 6,975-yard course.
Australian Jason Dawes came second after notching rounds of 68, 65, 70 and 71 for 14-under-par 274.
Dawes had shared the overnight runner-up slot with 16-year-old Thai amateur Chanin Puntawong, whose blazing 61 on Saturday equaled the Taiwanese Chung Chun Hsing's Asian PGA record for the lowest 18 hole score.
Chanin, the 2001 Junior World Golf Championship's winner, finished well out of the running Sunday in the 47th spot with a 9-over-par 81 for a 284 total.
Chen Yuan-chi of Taiwan, who after three rounds had been tied at 32nd, fired a final-round 7-under-par 65 to share third place with his countryman Lin Wen-tan at 13-under-par 275.
One shot behind them at 12-under-par 276 were Thai veteran and former Asian PGA Player of the Year Boonchu Ruangkit, and Myanmar's Aung Wing.
Overnight leader Loar, who was three shots clear of his nearest rivals after three rounds, shot a birdie at No. 2 before sinking two eagles at holes fourth and seventh.
The 25-year-old Dallas resident was seven strokes ahead until two straight bogeys at the 12th and 13th decreased his advantage into five.
Loar, last year Myanmar Open's runner-up, recovered to finish the final round with a three-under-par 69 to clinch the tournament's trophy as well as US$24,225 prize money.
'I'm really happy with the result today,' said Loar 'This is my first win after turning pro in 2000.'
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