The number of children under 17 years old in rural areas whose parents leave them with grandparents or other family members in order to earn money in cities has soared to 61.02 million, accounting for 37.7 percent of rural children and 21.88 percent of all children in China, according to the report.
The report was conducted based on demographic samples of 1.26 million people taken during the country's sixth population census in 2010.
Sichuan and Henan have the highest percentage of rural left-behind children, where 11.34 percent and 10.73 percent of local children barely see their parents.
Together with Anhui, Guangdong and Hunan, the five provinces house 43.64 of the country's rural left-behind children, the report said.
The report found that left-behind children are widely distributed in central and western provinces, which are the country's major labor sources.
But developed eastern areas also face similar problems, the report said.
More than half of children in Chongqing, Sichuan, Anhui, Jiangsu, Jiangxi and Hunan are left behind.
Guangdong province has the most left behind children with 4.34 million, accounting for 12.13 percent of the national total, followed by Zhejiang, Jiangsu, Shanghai and Beijing.
"The thing I'm worried most is the schooling of my kid, as I have no time to supervise her work," said An Baiyou, a truck driver from Shandong province, who has been leaving his 10-year-old child with his grandparents while driving freight vehicles in other provinces. "However, to earn the bread or take care of the kid, you can only cover one side."
According to Wang Zhenyao, director of the China Philanthropy Research Institute at Beijing Normal University, the left-behind children issue, if left unsolved, will pose a serious threat to the nation's future.
With the rural labor force surpluses continuously shifting to the city, left-behind children are more likely to have living quality, physical and psychological health issues than those who live with their parents, he said.
The country should consider setting up preferential policies to attract rural migrant workers in cities to return and work in their hometowns while speeding up the construction of new small towns, he said.
In addition, it's essential to establish a well-balanced child welfare system to protect the basic rights of young people, especially those with diseases, one parent and disabilities, he said.
These children are the future of the nation and deserve our loving care and protection, Wang said.