They will play the final against India at the same venue on Sunday (Sept 29). The match will kick off at 3:15pm (BdST).
India, the Group B champions, defeated Maldives by 4-0 goals at the same venue earlier in the day to book a place in the final.
The 3rd place decider between two losing semifinalists – Bhutan and Maldives – will also be held on Sunday at 11:15am (BdST) at the same venue.
Bangladesh, the Group B runners-up, dominated the first semifinal from the beginning. Tanbir Hossain, Maraz Hossain, Foysal Ahmed Fahim and Dipok Roy netted one goal each for the team.
They took the lead in the 16th minute when defender Tanbir netted the ball with a close range header inside the box, utilising a long throw in from another defender Kazi Rahad Mia.
Bhutan, who reached semifinal as unbeaten Group A champions, responded by attacking football.
But Bangladesh doubled the lead from a counter attack when forward Fahim netted the ball from a pass of midfielder Fahim Morshed in the 27th minute.
Three minutes later, Bangladesh was denied a goal by Bhutanese goalkeeper Tenzin Dorji. But in the 32nd minute, forward Maraz scored the third goal with a long range shot from outside the box (3-0).
Bangladesh missed another close chance to score from a counter-attack in the 36th minute.
Bhutan fought back in the second half and their attacking football produced some chances but they failed to utilise them.
Bangladesh continued their counter-attacks and got the final success in the stoppage time (90+2 minute) while substitute midfielder Dipok buried the ball with a long-rang left footer shot near the box (4-0).
“We’ve executed the plan successfully in the match and [the] boys performed well today against Bhutan,” Bangladesh Head Coach Andrew Peter Turner told a post-match media briefing.
Bangladesh: Shanto Kumer Ray, Sadekujaman Fahim, Yeasin Arafat, Tanbir Hossain, Kazi Rahad Mia, Maraz Hossain (Samrat Ahmed- 91st), Amir Hakim Bappi, Md Jamir Uddin, Foysal Ahmed Fahim (Omar Faruq Mithu-78th), Md Hridoy and Fahim Morshed (Dipak Roy-87th).
Bhutan: Tashi Tobgay, Dorji Khando (Jigdrel Wangchuk- 46th), Tenzin Norbu, Kelzang Jigmi (Kezang Dorji-46th), Tshelthrim Namgyel (Siddarth Gurung-80th), Loday Wangchuk, Karma Sonam, Pema Dendup, Yeshi Dorji, Kinley Tenzin, Tenzin Dorji
Referee: Phap Dias (Sri Lanka)