Goerges fell behind 5-2 in the first set before rallying to win 10 of the next 11 games as she cruised to her second straight WTA title.
"I can't imagine a better ending to this season, two titles in two weeks and this is the biggest one," said Goerges.
Goerges qualified late for the 12-player field in Zhuhai by winning the Kremlin Cup in Moscow two weeks ago. She has won nine matches in a row.
Vandeweghe, who entered the tournament seeded second, dropped five service games against Goerges.
"I felt a little flat today but Julia played really well," said Vandeweghe. "She finished by having a great two weeks. I'm just a little bit disappointed by how flat I came out for a final."
Goerges will move up to a career high of 14 in the year-end WTA rankings.
The tournament in Zhuhai features the leading players on the women's tour who didn't qualify for the WTA Finals in Singapore last week. The 12-player draw was divided into four groups of three, with the winner of each group advancing to the semifinals.