China's census shows its population was 1.33 billion people at the end of 2010, with a sharp rise in the number of people over the age of 60.
That represents an increase of 70 million since the last census in 2000.
The figures show, however, that the rate of population growth has slowed considerably and is now at just over 0.5%.
This is attributed to the government's strict controls on family size, including its one-child policy for most urban families.
Some demographers say the limits on family size may now threaten China's economic growth.
The census carried out in November 2010 shows nearly 50% of Chinese live in urban areas.
Of these, 220 million are classed as migrants - people who have left their homes in rural China to travel to the huge coastal cities and factories looking for work.