World No. 1 Axelsen won his second world title, beating the Thai 21-5, 21-16 in a one-sided final.
The 21-year-old Kunlavut, a three-time junior world champion and ranked world No. 17, had raised hopes of becoming the first Thai to win the men’s title after toppling Singapore's defending world champion Loh Kean Yew in the quarter-finals.
Axelsen’s previous world title had come in Glasgow in 2017.
The 28-year-old Dane, the Olympic gold medallist, did not drop a game throughout the tournament.