Of about 6.3 million square kilometres of soil surveyed -- roughly two thirds of China's total area -- 16.1 per cent is thought to be polluted, the environmental protection ministry said in a report.
The study, which appeared on its website, blamed mining and farming practices among other causes.
"The national soil pollution situation is not positive," the ministry said, adding that more than 19 per cent of the farmland which was surveyed is polluted.
The government has come under increasing pressure in recent years to take action to improve the environment, with large parts of the country repeatedly blanketed in thick smog and waterways and land polluted.
In response to public pressure, China has released more accurate data about air pollution.
More than 80 per cent of the soil pollution was caused by "non-organic contaminants", the ministry said in its report.
The survey was carried out over an eight-year period from 2005 to 2013.
Premier Li Keqiang announced in March that Beijing was "declaring war" on pollution, as he sought to address public concerns on issues ranging from smog to food safety, but experts warn that implementation will be the key.
