Openers Alyssa Healy and Phoebe Litchfield made light work of a 199-run chase, sealing victory in just 24.3 overs.
The result took Australia to the top of the group standings with nine points from five matches, while defending champions Bangladesh remained in sixth place with only two points.
Healy led from the front with a blistering unbeaten 113 from just 77 balls, smashing 20 boundaries in a dominant display that marked her second century of the tournament. Litchfield was equally composed at the other end, finishing 84 not out with 12 fours and a six. The pair's unbroken 199-run opening stand was one of the most commanding partnerships of the competition.
Earlier, Sobhana Mostary's resilient knock had helped Bangladesh post a respectable 198 for 9 after being put in to bat. Mostary remained unbeaten on 66 off 80 balls, striking nine fours and accelerating late in the innings with 28 runs coming off the final three overs. Rubya Haider added a valuable 44, but regular wickets prevented Bangladesh from building momentum.
Australia's bowlers were once again on target, with leg-spinners Alana King (2 for 18) and Georgia Wareham (2 for 22) proving particularly effective. Ashleigh Gardner (2 for 45) and Annabel Sutherland (2 for 42) also shared wickets despite being slightly expensive, while Megan Schutt picked up the first breakthrough to remove Farzana Haque.
Bangladesh slipped from 67 for 1 to 165 for 9 before Mostary's late hitting ensured they were not bowled out, the first time Australia failed to dismiss a side completely in this tournament.
But any hopes of an upset quickly vanished as Healy and Litchfield dominated from the outset, guiding the six-time champions to a flawless victory and yet another semi-final berth in their illustrious World Cup history.
Matt Renshaw struck a career-best 89 not out from 52 balls to help Australia beat Bangladesh by seven runs in the second T20I as the visitors took an unassailable 2-0 lead in the three-match series.
Australia cantered to a nine-wicket victory against Bangladesh while India beat Netherlands in a double-header at the ICC Women's T20 World Cup in Leeds on Wednesday.
Joel Davies starred with the ball on international debut to help Australia beat Bangladesh by four wickets in the first of three T20Is in Chattogram on Wednesday.
Bangladesh ODI captain Mehidy Hasan Miraz says healthy competition in the squad and a conscious effort to prepare better pitches at home has contributed to their improved form.
