The 26-year-old Romanian world number one, still seeking a first grand slam title, trailed 3-0 but battened down the hatches to reel off the next nine games on her way to a first Melbourne semi-final.
An increasingly deflated Pliskova eventually stopped the rot but with Halep offering precious little in the way of cheap points, the result soon became a formality.
Halep made only 10 unforced errors in the one hour, 11 minute contest on Rod Laver Arena and sealed victory with a deep return which Pliskova could only slap into the net.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
She described the performance as her best of the tournament so far but she might need to go up another level in the semi-final, where she faces the in-form 2016 Melbourne champion Angelique Kerber.
"I think this was a great match. The best this tournament. I started slow but then I got used to the rhythm. I got used to everything. I played very well," she said.
"You never know with her because she has crazy good shots sometimes and also the serve. But I read her serve many times today. I just was very strong on the return."
There was early encouragement for Pliskova as she held an extended opening service game then cracked a forehand winner to earn a break point, which she converted when Halep missed a forehand over the baseline.
When she held for 3-0 there was no hint of what was to come.
Halep, saved a break point in the next game as Pliskova netted a routine forehand, then settled into her usual groove and the errors began to flow from across the net.
Pliskova surrendered the opening set with a double-fault and dropped serve again to trail 2-0 in the second.
Halep, who said she was untroubled by the ankle problem that has bothered her at times here, was never going to lose her grip from there, even if Pliskova did offer some late resistance.
Pliskova was left to rue the chance she had to make it 4-0.
"That was a huge game to go a double-break up," she said after Halep improved her head-to-head record against the Czech to 6-1.
"It would be not for sure, but most probably my set, the first one. I don't think I did something that wrong. Maybe just the big points I play bad against her, then it changes quickly.
"I think all the matches we play are pretty similar. I feel she just likes my game."
(Reporting by Martyn Herman; Editing by John O'Brien)
