Myanmar, who had lost to Malaysia in the final of the Merdeka Tournament last year and also in the semi-finals of the same tournament last month, scored two goals in each half for the win.
Myat Min scored twice in the first half (25th and 45th minute) before adding the third in the 89th minute as Aung Kyaw Moe then delivered the final blow deep in injury time.
Malaysia’s only goal in the game came off Amirulhadi Zainal in the 75th minute.
Both Myanmar and Malaysia are using this tournament as part of their preparation for the AFF Suzuki Cup 2008 next month.
Myanmar are in Group A which will be based in Jakarta against hosts Indonesia, Singapore and Cambodia.
Group B in Bangkok are Thailand, Malaysia, Vietnam and Laos.
In the other semi-final, Indonesia will take on Korean club team Ulsan Hyundai Horang-i.