The event will be held from November 1-4 at Amata Spring Country Club in Thailand.
Thongchai, who won the Wales Open on the European Tour in June, is considered Thailand's most famous and successful golfer, and he will be an inspiration to his young compatriots ahead of the fourth edition of the Asia-Pacific Amateur Championship. The event, which offers free entry to spectators, is organised by the Asia Pacific Golf Confederation (APGC), the Masters Tournament and The R&A.
As the host nation, Thailand could have up to 10 players competing in the 120-man field and many will have their eyes on more than just the event's trophy.
Each year, the winner earns an invitation to compete in the Masters Tournament at Augusta National Golf Club, while the champion and runner(s)-up both earn spots in International Final Qualifying (IFQ) - Asia for The Open Championship.
"This is an exciting opportunity for Thailand to host the Asia-Pacific Amateur Championship as it will give our best young golfers a chance to compete against other top amateurs in the region, as well as an opportunity to earn a spot in the Masters and IFQ-Asia," said Thongchai, whose duties will include meeting the Thailand team and speaking on behalf of the championship and the host nation.
"When I was a young amateur, we were not exposed to the exciting opportunities that this championship presents. Qualifying for the Masters and IFQ-Asia will certainly inspire fierce competition at Amata Spring."
Thongchai, a former paratrooper in the Royal Thai Army, had a successful amateur career and won two individual Putra Cup titles, the Thailand Amateur Open and Singapore Amateur Open before he turned pro in 1999 at the age of 30.
Now 42, Thongchai is the Asian Tour's most accomplished player, with three Order of Merit titles and 13 victories. He was the first Thai to compete in all four Majors, including The Open Championship six times and the Masters twice, and has also won five European Tour titles.
Thongchai believes that the Thai golfers will make the most of home advantage in this year's Asia-Pacific Amateur Championship, with the likes of Natipong Srithong and Poom Saksansin expected to be among the line-up.
"The Thai players did well last year in Singapore, with Natipong Srithong finishing 17th, but we'll have more players this year as the host nation and a better chance because we're playing in our country. We'll also have the support of the Thai golf fans, which will be a huge boost for our young players," Thongchai said.
"Hosting the Asia-Pacific Amateur Championship is also a big boost for golf in Thailand as we have the chance to welcome players from countries all across Asia-Pacific and show them our great golf facilities and Thai hospitality."
Thongchai is expected to meet with some of the Thailand players once the team is finalised later this month and pass on some advice, including how to play Amata Spring, which is located outside Bangkok in Chonburi.
Thongchai has competed at the prestigious club on many occasions, including in the Royal Trophy team event between Europe and Asia, last year's Thailand Golf Championship and a 2010 skins contest also featuring Tiger Woods, Paul Casey and Camilo Villegas.
"I know the players will all be impressed by Amata Spring, as I've played there many times. Amata Spring is an outstanding venue and I know it will be a fantastic host of this international event, which is growing in importance and stature each year," Thongchai said.
"I've played at the Masters and The Open Championship, so I know that the organisers of these events will also ensure the Asia-Pacific Amateur Championship is run like a world-class professional event, and I also know Amata Spring and Thailand will prove excellent hosts."
Hideki Matsuyama won the 2010 and 2011 editions and the Japanese star has confirmed he will defend his title in November. Matsuyama's two victories earned him invitations to the Masters, where he finished 27th in 2011 to win the Silver Cup as low amateur, and again made the cut this year, finishing 54th.
This year's field will include up to 120 players from the member nations of the APGC. Each nation automatically receives two invitations, based on the WAGR as of August 29. The rest of the field is then made up of invitations by ranking, with each country allowed up to a maximum of six players, while Thailand can have up to 10 as the host nation.