Playing in Leeds, Bangladesh endured a disappointing all-round performance, posting just 77 for 8 in 20 overs after being asked to bat.
Australia then chased down the modest target with ease, reaching 78 for 1 in just 9.3 overs.
Bangladesh's batting struggled from the outset, with only two players reaching double figures.
Captain Nigar Sultana top-scored with a painstaking 27 off 47 balls, while Ritu Moni contributed 16 from 26 deliveries. The rest of the batting line-up failed to offer resistance as Bangladesh fell well short of the 100-run mark.
Australia's bowlers shared the workload efficiently, with Kim Garth, Ellyse Perry and Sophie Molineux claiming two wickets each to restrict Bangladesh to one of their lowest totals in the tournament.
In reply, Australia lost their only wicket at 31 when Marufa Akter dismissed Beth Mooney for 10 in the fifth over. However, that breakthrough only delayed the inevitable.
Georgia Voll led the chase with an unbeaten 45 off 32 balls, while Ellyse Perry added an unbeaten 19 from 15 deliveries as Australia cruised to victory without any further setbacks.
Bangladesh had opened their campaign with a win, but they were outclassed in every department against the six-time champions, who secured a dominant victory to strengthen their position in the tournament.
