The 23-year-old Grace, from South Africa, finished at 21-under 267 at Binhai Lake. He won the Joburg Open and Volvo Champions in consecutive weeks in South Africa in January.
"To get three before the start of May is unbelievable. But I have been playing well, getting myself into contention and making the most of the opportunities," Grace said. "At first I was thinking about trying to keep my playing card this year, but now I feel I have the ability to go out and win every week and I have had that mindset for some time."
Colsaerts, the winner last year at Luxehills, also shot a 69.
The event also was sanctioned by the OneAsia Tour and China Golf Association.