During the glaring incident caught on camera, Xi stoically stared ahead for photographs and then glanced at Prayuth who bowed before him and offered his hand, which Xi spurned, leaving the Thai leader visibly bewildered.
The awkward encounter comes as United States officials have fretted about Thailand warming up to China.
After Xi ditched him, Prayuth looked around with his hand out seemingly perplexed. He then exited the stage with his wife.
The 2022 APEC summit is taking place in Bangkok, Thailand.
Earlier this week in another unvarnished moment caught on film, Xi dressed down Canadian Prime Minister Justin Trudeau for leaking details about a meeting the pair had to the press. Xi’s confrontation took place on the sidelines of the Group of 20 leaders summit earlier this week.
But even Trudeau got a handshake from Xi.
It is not immediately clear if the cold shoulder given to Prayuth was intentional or a mere misunderstanding.
China’s appearance at APEC has been overshadowed by the war in Ukraine and missile activity in North Korea.
Xi recently sailed to a third five-year term as the head of China and further solidified his grip on power by elevating many of his acolytes to key positions. During one of the Chinese Communist Party meetings before Xi’s coronation, his predecessor Hu Jintao was mysteriously escorted out of the room, a jarring moment that drew international attention.
Chinese officials have chalked up the incident to Hu’s age, suggesting that at 79 he suffered a moment of delirium.