Top seed and defending champion Rybakina cruised through the opening set but was forced into a decider by the 128th-ranked Kawa before sealing a 6-1, 3-6, 6-1 victory.
Moscow-born Kazakh Rybakina will face Russian sixth seed Diana Shnaider in the last four in eastern China.
Shnaider overcame US fourth seed Iva Jovic in three sets. Canada's Leylah Fernandez plays Marie Bouzkova of the Czech Republic in the other semi-final.
Rybakina, 27, won the US Open for her third Grand Slam crown in September and usurped Aryna Sabalenka as world number one in New York.
She was then stunned in the second round in Beijing at the start of this month, and pulled out of the Wuhan Open citing a foot injury.