While China’s leaders weigh what to make of Donald Trump’s impending presidency, one manufacturer in the scenic city of Shaoxing has been enthusiastically carrying Mr. Trump’s banner.

Or, more accurately, he’s been printing, folding and shipping it.

Yao Dandan is the owner of Shaoxing Jiahao Banner and Handicrafts Co. Ltd. Since election results suggesting a Trump victory began pouring in Wednesday morning, he says, he’s fielded a barrage of orders for Trump-themed flags.

The total number ordered as of Thursday morning: more than 40,000.

“I knew there would be demand for Trump flags after the election, so I made extra. But it’s not enough, so now I have to make more,” Mr. Yao said.

The 30-year-old said that he’s been in the flag-making business for a decade and that Shaoxing’s factories specialize in making election banners. His factory has taken orders for close to half a million Trump banners in the past two months, he said.

Mr. Trump has taken heat for vowing tough restrictions on Chinese imports while over the years turning to China to source goods ranging from ties to steel, but there’s no evidence the next U.S. president purchased banners from Shaoxing. Mr. Yao said most of the orders he’s received came from Chinese clients living in the U.S.

Flags bound for the U.S. have to be higher quality than most, he said. He charges 2.5 yuan ($0.37) a piece for the smallest Trump banners, which his clients typically sell in the U.S. for between $1 or $2 (they sell for 5 yuan on e-commerce site Alibaba). The factory has produced every U.S. state flag, and earlier this year got multiple orders for Confederate flags.

What about orders for Hillary Clinton banners? Mr. Yao, who counts himself a Trump supporter, said he’s been asked but now refuses to make them because he believes Mrs. Clinton is unfair to China.

The news of Trump’s win was “a pleasant surprise,” he said. “It means I didn’t strive these past couple of months in vain.”

Asked about Mr. Trump’s vow to impose a 45% across-the-board tariff on Chinese goods, Mr. Yao confessed he wasn’t aware of that part of the property mogul’s platform but said he thought China’s government would make sure it wasn’t implemented.

The flag-maker said he’d never been to the U.S. but planned to remedy that soon.

“When things slow down, I'm going to go to the U.S. and have a look. At the very least I also contributed a little!" he said.

-- Olivia Geng and Josh Chin