She is 26 and has been on the pro circuit for the last 11 years.
Muguruza's world No 1 position is under threat after she bowed out of this tournament in the first round with a virus.
China's Peng Shuai coasted to a 6-3, 6-2 triumph over Monica Niculescu of Romania to set up a match against Latvian Jelena Ostapenko, who notched a 6-3, 7-5 win over Australian Samantha Stosur in 1 hour, 48 minutes.
"It was a great match, I think I played my best tennis against her", Halep told the WTA Insider. Along the way, Halep will become the co-author of a repetition of the record for the second time in history during the season on top of the world rankings will be five players (Angelique Kerber, Serena Williams, Karolina Pliskova, Garbine Muguruza and Simona Halep).
Simona Halep ends her wait to top the WTA World Rankings by reaching the final of the China Open with a win over Jelena Ostapenko.
Halep and Ostapenko met at the French Open earlier this year, with the Latvian winning the duel.
The former world No. 1 was forced to retire during her Beijing opener due to illness. "It's my first victory against her and I just want to enjoy the moment".
That said, with 9 of the Top 10 players entered (only Venus didn't make the trip), Simona Halep was the only Top 8 player to make the semifinals.
Halep, who a year ago was defeated in the round of 16 in Beijing, won 149,138 United States dollars and 215 WTA singles points.
"I think she played an incredible match, probably the best she's played against me in all of our previous meetings", she said.
Kvitova, who produced 33 winners offset by 43 unforced errors, said she was exhausted but very happy with the victory, and will meet Caroline Garcia in the last four.