The win helped the Vietnamese side move a step close to a place in the quarter-finals.
Do Thi Nguyen’s hat-trick was the highlight of the seven goals scored by Vietnamese girls during the match.
Earlier, Vietnam beat Chinese Taipei 1-0. They will next face Malaysia on May 6.
Group B of the second AFC Women’s Futsal Championship comprises Vietnam, Malaysia, Bangladesh and Chinese Taipei.
The tournament is underway in Bangkok from May 2 to May 12.
Reigning champions Iran is in Group D with Uzbekistan and Turkmenistan.
Thailand who finished third in the 2015 championship and host this year’s event face Hong Kong, Indonesia and Macao in Group A.
Japan, the runners-up, are playing China, Bahrain and Lebanon in Group C.-VNA