The 24-year-old Italian becomes the first player to reach all three finals of the season's first three Masters 1000 events since Novak Djokovic in 2015.
Roger Federer, in 2006, and Rafael Nadal, 2011, are the only two other players to achieve the feat.
"I'm very happy," said Sinner.
"We came here trying to give myself some feedback (on clay) and now finding myself in the final means a lot to me."
Sinner said he had felt in top form right from the outset of the match against his German opponent, ranked third in the world.
"Obviously, every match, every day is different, so I'm very happy about today’s performance. I felt really solid from the beginning.
"When you are a break up straight away, it changes the dynamic of the match, so very happy and let's see what's coming in the final."
As in Indian Wells and Miami, Sinner had the measure of Zverev, who has not prevailed in their meetings since the round of 16 at the US Open in September 2023.
Extremely aggressive from the start, he blew the German away in the opening set, breaking him three times and wrapping it up in 34 minutes.
In the second set, the German put up more resistance, finding his first serve again, but he still had to battle every time to hold.
He finally folded after 1hr 22min on another blistering forehand from Sinner, who has lost only one set in his last 21 matches at Masters 1000 events.
Sinner will face world No.1 and defending champion Carlos Alcaraz in the final after he beat local boy Valentin Vacherot 6-4, 6-4, ranked 23 in the world, later on Saturday.
It'll be the first meeting this season between the world's top two players, which will decide who will be world No.1 come Monday when the new ATP rankings are released.