Between 1978 and 2015, more than 4 million studied internationally; 2.2 million returned

China has the largest number of students studying overseas and they play a key role in the trends of international student mobility, according to a report.

China had a total of 1.26 million students overseas as of 2015, accounting for 25 percent of the world's total number of students studying outside their native country, meaning one in four such students is from China, according to the 2016 Report on the Development of Chinese Students Studying Abroad.

The report was released by the Center for China and Globalization think tank in Beijing on Monday. It was the fifth time that the annual report has been released.

The report said China is the largest origin of international students for English-speaking countries including the United States, the United Kingdom, Canada and Australia. Meanwhile, Chinese students also make up the largest proportion among international students of countries in the "Chinese-culture circle", such as Japan, South Korea and Singapore.

"Because of their large numbers, Chinese students and their mobility have a big impact globally," the report said.

The report also found that more students are returning to China after finishing their studies overseas. Official statistics show that more than 4 million Chinese studied abroad between 1978 and 2015, with 2.2 million of those returning to China.

In recent years, the gap between the number of those going abroad and returning each year has been further narrowed, the report said.

However, those returning also face more challenges, as the number of such graduates has increased rapidly, the report added. More than 60 percent of graduates returning from overseas study are taking entry-level posts and a majority of them are not content with their jobs.

About 12 percent of them choose to start their own businesses and favor entrepreneurships in strategic, emerging industries such as bioengineering and information technology. They prefer to work in first-tier cities such as Beijing, and Shanghai, but many have encountered difficulties such as high costs and other financial issues.

Miao Lu, secretary-general of the think tank, said measures should be taken to create a better environment for graduates returning from overseas to work or start their own businesses in China.

"In addition, obstacles should be further removed to allow such graduates to join all levels of government departments, public institutions and State-owned enterprises," Miao said.