The projections for 2015, which will mark the first time city dwellers outnumber the rural population, also indicate people age 60 or over will top 200 million, said Li Bin, director of the National Population and Family Planning Commission.
An average 8 million people will turn 60 each year between now and 2015, 3.2 million more than between 2006 and 2010, Li said in a speech at the annual conference of the China Population Association in Nanjing, the capital of east China's Jiangsu Province.
China's working-age population, between ages 15 and 59, will begin to fall after 2015, the state-run Xinhua news agency cited her as saying.
This will lead for the first time in more than 40 years to a growing population too young or too old to work, and possibly too few young workers to support an aging population, Xinhua said.
However, China will still have a plentiful labor supply and a relatively low population dependency ratio, Xinhua cited Li as saying.
Chinese government statistics indicate China's population, the world's largest, was 1.32 billion at the end of 2008 -- about 2.5 times the 1949 population, when the People's Republic of China was founded.
To slow China's fast population growth, the government adopted a policy in the late 1970s of generally limiting families to one child. The policy slowed China's population increase to less than 40 percent between 1978 and 2008, after nearly doubling between 1949 and 1978, Xinhua said.