Three goals in each half did the trick for the junior War Elephants, with striker Chananan Pombubpha leading the way with four goals, while Peerpat Notechaiya contributed three assists.
Right-back Narubadin Weerawatnodom opened the scoring in just the 10th minute when he got on the end of Notechaiya's corner.
Pombubpha opened his account in the 19th minute, applying the finish after some great interplay between Chanathip Songkrasin and Pinyo Inpinit
After the early shock of going two-down, Lao began to find their feet more and Thailand goalkeeper Chanin Sae-ear was forced to make a smart save to deny Soukaphone Vongchiengkham.
However, it was Thailand who would strike next, with Nurul Sriyankem's thunderbolt in the 38th minute leaving Vathana Keodouangdeth with no chance.
If Laos had hoped to use the half-time break as an opportunity to slow Thailand's charge, they were dealt a hammer blow when Pombubpha grabbed his second of the game just two minutes into the second period to make it 4-0.
Pombubpha completed his hat-trick in the 62nd minute, converting from the penalty spot after Vongsa Thinnakone brought down Sriyankem inside the box.
Laos were unable to curb the tide and Thailand added a sixth in the 74th minute, with Pombubpha heading home a beautiful cross from Tristan Do to wrap up the scoring for the match.