The world number one, who lifted the trophy in Doha for a third consecutive time last Saturday, extended her unbeaten streak to seven matches and is looking to become the first woman since 2007, and just the third overall, to win both Gulf tournaments in the same season.
In what was their sixth meeting in the span of 20 months, Swiatek came up clutch when she needed to as she improved to a perfect 6-0 lifetime against Zheng.
"I'm happy that I played well, stuck to my tactics, was pretty solid. For sure I feel better and better every day here," said Swiatek, who was a finalist in Dubai 12 months ago.
The Polish top seed will next take on Russian world number 40 Anna Kalinskaya, who upset world number three and reigning US Open champion Coco Gauff 2-6, 6-4, 6-2.
An early break of serve was enough for Swiatek to secure the opening set, outlasting Zheng in some key powerful baseline battles to take the lead in 42 minutes.
Swiatek had to save a break point in game four before pouncing on the Zheng serve and she didn't lose another game, sprinting to victory in one hour and 26 minutes.
The four-time Grand Slam champion will be facing Kalinskaya for the first time on Friday.
Kalinskaya, who reached her first major quarter-final at last month's Australian Open, posted the sixth top-10 victory of her career with a comeback effort against Gauff.
The 25-year-old is just the fourth qualifier to reach the semi-finals of the WTA tournament in Dubai.
Kalinskaya needed medical attention for an upper back issue late in the first set but managed to recover in the second and cruised in the third to stun Gauff in two hours and 17 minutes.
Six match points saved
"I'm super happy about my game here," said Kalinskaya, who will contest her first WTA 1000 semi-final.
"She's a great player, a great fighter. I could feel the tension until the last point, so it was very important from my side to stay focused and calm and just do my best and trying to stay aggressive."
Meanwhile, world number four Elena Rybakina withdrew ahead of her scheduled quarter-final, citing a gastrointestinal illness.
Having won the title in Abu Dhabi, made the final in Doha and the last-eight stage in Dubai, Rybakina tallied up 10 wins from 11 matches contested across three cities in the span of 14 days in the Middle East.
The former Wimbledon champion also picked up a trophy in Brisbane last month and leads the tour with 17 victories and just three losses in 2024.
Rybakina's decision to pull out of the tournament sends Italian Jasmine Paolini into the semi-finals of a WTA 1000 event for the first time in her career.
Paolini will next take on Romanian Sorana Cirstea, who said she pulled off the "biggest comeback of my career" after rebounding from 2-6, 1-5 down and saving six match points to defeat reigning Wimbledon champion Marketa Vondrousova 2-6, 7-6(1), 6-2.
The seventh-seeded Vondrousova served for the match on three different occasions in the second set but couldn't close, allowing Cirstea to fight back and book her place in the third WTA 1000 semi-final of her career.
At 33 years of age, the 22nd-ranked Romanian is the oldest semi-finalist in the history of the WTA tournament in Dubai.
"I'll be honest, I didn't expect to win this one being down a set and 5-1," admitted Cirstea, who now owns two top-10 victories in 2024.
"I looked over at the clock and I saw it was only one hour of play. I was having such great support. I said, 'Okay, let's try to win one more game for the public, make it a little bit longer'. I think that thing took the pressure away from me."
