It looked as though the Matildas, who booked their place in Rio 2016 after Monday's 2-1 win over North Korea, would be made to pay for a slightly lethargic start to the clash, which decided the winner of the AFC Women's Olympic qualifying zone.
But Australia continued to push in the second-half and van Egmond's stunning long-range strike ensured the Matildas ended their qualifying campaign on 13 points from five matches, with China finishing on 11 points.
Earlier, China went ahead in the 16th minute through Ma Xiaoxu's header, after getting the better of Australia defender Laura Alleway in the air.
The Matildas had a chance to hit back just two minutes shy of half-time through Kyah Simon, who had bagged four goals in as many qualifiers leading into the contest, but the 24 year-old fired wide from an acute angle.
Despite having the better of most of the second-half exchanges, it looked as though Australia would be frustrated but their never say die attitude shone through as van Egmond restored parity late on.