It was the hosts which started the contest with the upper hand when Sun Pingwei's header from Shen Menglu's cross gave China the lead four minutes into the encounter.
Four minutes later, Yang Shuhui's cross located Yang Qian inside the area with the latter's header, doubling the lead for the Steel Roses.
Comeback hopes for Sheryl Botes' side were buried when Han Xuan fired past goalkeeper Kaydee Windvogel late on to guarantee her side the Chinese four-nation tournament title.
In the other match, Vietnam played out a 0-0 draw with their Asian rivals Thailand at Haicang Sport Centre Stadium.
Friday's results meant China clinched the title, finishing with seven points, followed by Thailand and Thailand with five and four points respectively, while South Africa finished at the bottom with no point.
Having ended their Chinese tour, South Africa will return home on as they look to continue their build-up to the COSAFA U20 Women's Cup and Fifa U20 Women's World Cup qualifier later this year.