In-form opening batter Alyssa Healy led the way for the six-time champions with 72 off 79 balls, supported by 35 from skipper Meg Lanning and 34 from Rachel Haynes.
Pakistan captain Bismah Maroof scored 78 as her team made 190-6 after losing the toss and being put into bat.
Despite a much-improved performance on their first-round loss to India, Pakistan paid the price for a sluggish run rate.
Allrounder Aliya Riaz made a creditable 53 but it came off 109 balls, while Australia’s top order scored at almost a run a ball.
The result puts Australia top of the tournament’s eight-team leaderboard but leaves Pakistan bottom with a struggle to make the final four after two losses.
“Everyone’s in really good form, we all got starts and I guess we’re all feeling in good nick,” Lanning said.
“Pakistan did extremely well and made it hard for us to take wickets so we were disciplined and kept that run rate in check.”
Pakistan’s total never looked enough against Australia’s formidable big hitters, who overhauled the target with 15.2 overs to spare, finishing on 193-3.
Maroof said Pakistan were unable to exert pressure in the field.
“We could have stopped them, they gave us chances but we didn’t capitalise,” she said.
“In fielding we could have done much better.”
Defeat left Pakistan without a win against Australia in 13 ODI matches.
Pakistan face South Africa on Friday while Australia’s next challenge is against hosts New Zealand on Sunday.
