In difficult conditions under pouring rain at the London Stadium, Hungary's Anita Marton claimed silver with 19.49.
After claiming six major silver or bronze medals since the 2008 Olympic Games, the 28-year-old Chinese athlete managed a best of 19.94 metres for her country's first gold medal of the championships.
In difficult conditions under pouring rain at the London Stadium, Hungary's Anita Marton claimed silver with 19.49, while American Olympic champion Michelle Carter took bronze (19.14).
Gong was left delighted with China's first shot title since Huang Zhihong won her second gold in Stuttgart in 1993, saying: "I was a bit worried about my condition because two years ago I was heading for gold and I changed a couple of things after the Olympic Games in Rio."
"I competed more this year to be ready for these championships."
"It is 24 years since China won a shot put medal, so it's a very special moment for me. Of course, the rain affected the competition and that is the reason we didn't go past 20 metres tonight."
Gong added: "My next goal is, of course, the Tokyo Olympics. My memories of London 2012 are mixed because I was third originally, then I was moved to second later. I didn't like the way that happened."
"So I am glad to show all the hard work I've done in the past with this gold medal."