When Chen Ning returned to the country to get his startup going, he had to share an office with another maker, but two years later he has an office of more than 1,000 square meters with about 100 employees in Shenzhen.

Chen said: "The attraction of Shenzhen is the city's recognition of new technology." It was willing to provide resources to try out Chen's product, an opportunity he cherished the most.

Technology is one of the most important advantages of many overseas returnee entrepreneurs, he said.

Chen received his doctorate at the Georgia Institute of Technology in the United States. When working overseas in the frontiers of chip R&D industry, he once participated in setting the international standard of 4G-LTE.

His startup, named Intelli-Fusion Technologies Co Ltd, focuses on the research and development of artificial intelligence and visual information processing. Its production value reached 50 million yuan ($7.24 million) last year.

Shenzhen's public security system in 2015 adopted the startup's first visual intelligence system "DeepEye", which can help recognize a suspect from a million people in just one second.

Chen said the public security market was their major target. Thanks to Shenzhen's successful pilot project, he can promote the model to other Chinese cities this year. "Only when advanced technology is combined with market demand can innovative startups perform to the best of their abilities," said the 41-year-old entrepreneur.

As for financial support, his team was enrolled in Shenzhen government's "peacock campaign", a program to attract tech talent, and was granted 40 million yuan in capital support in 2015. Since 2011, the program has supported more than 1,200 top talented people and about half of them have overseas study background.

People with overseas study backgrounds are among the many startup founders in Shenzhen, including those of high-tech enterprises like DJI, Kuang-Chi, Royole and BGI.

In 2016, Shenzhen attracted 10,509 such talented people, a record high, with financial incentives, housing subsidies and other preferential measures. Yang Peng, head of the Shenzhen Overseas Chinese Returnees Association, said Shenzhen is the preferred destination for overseas returnees to start their own businesses.

According to the association's survey, about 10 percent of the city's overseas returnee students choose to set up startups there.