SHANGHAI, 26 Apr 2015 (AFP) - Wu, who recorded a four day total of 279, or nine under par, became the first Chinese player to win a European Tour event held in China, according to information provided by tournament organisers.
"It’s a wonderful day today," the 29-year-old Wu said.
"It’s very special winning the China Open and it’s very exciting."
England's David Howell finished second in the $3.2 million tournament, shooting a final round 72 to finish at 280.
The day was not without drama. Howell failed to make an eight foot putt for par on the final hole that would have forced a playoff with Wu.
Alexander Levy of France, the defending champion, slipped to a one over 73 and finished in a three-way tie for third at 281 with Emiliano Grillo of Argentina and Prom Meesawat of Thailand.
The tournament, which was played at the par 72 Tomson Shanghai Pudong Golf Club, is co-sanctioned by the European and OneAsia Tours.
No one has managed to win it in consecutive years in its 21-year history.
China's Li Haotong, meanwhile, shot a final round 74 to finish a stroke behind Levy, Grillo and Meesawat at 282.
Wu, Howell, Levy and Li had started the day in a four-way tie for the lead.
The 19-year-old Li, regarded as a potential golfing superstar, won three times on the PGA China Tour in 2014.
The tournament was the 49th European Tour event played in China, according to the organisers.
Leading scores on Sunday after the fourth and final round of the European Tour's Volvo China Open at the Tomson Shanghai Pudong Golf Club, Shanghai, China (par 72):
279 - Wu Ashun (CHN) 73-66-69-71
280 - David Howell (ENG) 68-72-68-72
281 - Emiliano Grillo (ARG) 73-70-69-69, Prom Meesawat (THA) 72-70-68-71, Alexander Levy (FRA) 69-68-71-73
282 - Li Haotong (CHN) 71-68-69-74
283 - Richie Ramsay (SCO) 72-68-70-73
284 - An Byeong-Hun (KOR) 72-68-76-68, Romain Wattel (FRA) 72-67-74-71, Peter Uihlein (USA) 70-67-76-71, Tyrrell Hatton (ENG) 75-69-69-71, Julien Quesne (FRA) 69-67-76-72, Magnus Carlsson (SWE) 73-72-65-74