More than 60 crimes can carry the death penalty in China
The Chinese authorities put to death at least 470 people last year, but probably killed many more, human rights group Amnesty International has said.
Amnesty said the hidden extent of executions in China, where figures are secret, might mean the Olympic host was behind the bulk of them worldwide.
But China's foreign ministry defended the death penalty, saying China limited it to a small number of criminals.
At least 1,252 people are known to have been executed in 24 countries in 2007.
Just five countries - China, Iran, Saudi Arabia, Pakistan and the US - were responsible for 88% of known executions in the world, Amnesty said.
About 3,347 people were sentenced to death in 51 nations last year and up to 27,500 people are now estimated to be on death row.
In its annual report on the death penalty, Amnesty International said China had executed more than any country last year.
While there were 470 confirmed executions, the real figure was likely to run into thousands, Amnesty said.
"As the world's biggest executioner, China gets the 'gold medal' for global executions," said the organisation's UK director, Kate Allen.
More than 60 crimes can carry the death penalty in China, including tax fraud, stealing VAT receipts, damaging electric power facilities, selling counterfeit medicine, embezzlement, accepting bribes and drug offences, Amnesty said.
Those sentenced to death are usually shot, but some provinces are introducing lethal injections, which the government says is more humane.
The BBC's Quentin Sommerville, in Beijing, says justice is usually swift - most of those sentenced to death are executed only weeks after they are found guilty.
GLOBAL EXECUTIONS IN 2007
Minimum of 1,252 people were executed in 24 countries
At least 3,347 sentenced to death in more than 50 countries
Up to 27,500 on death row
China: at least 470, many more estimated
Iran: at least 317 people
Saudi Arabia: at least 143,
Pakistan: at least 135
In a statement responding to the Amnesty report, Chinese Foreign Ministry spokeswoman Jiang Yu said: "The conditions are not right in China to abolish the death penalty, and would not be supported by the majority of the people."
"We severely control and cautiously use it, to ensure that it is only used in a small minority of the most serious cases."
The Chinese government has recently attempted to reform the system.
Last year, it decreed that all cases involving the death penalty had to be referred to the Supreme Court. According to state media, this led to a 10% fall in executions in the first five months of 2007.
Amnesty urged the International Olympic Committee and athletes to press for greater openness about executions during the Olympic Games in Beijing this August.
"The secretive use of the death penalty must stop: the veil of secrecy surrounding the death penalty must be lifted," it added.
"Many governments claim that executions take place with public support. People therefore have a right to know what is being done in their name."
Iran was second to China with 317 known executions during 2007, the report said, followed by Saudi Arabia on 143, Pakistan on 135 and the US on 42.
Amnesty said the totals had risen alarmingly in Iran, Saudi Arabia and Pakistan, but that worldwide they showed a drop - down to 1,252 from 1,591 the previous year.
Iran was second to China, with 317 known executions in 2007
The executions in Iran included the stoning to death of a man for adultery, and the execution of three people who were teenagers aged between 13 and 16 at the time of their arrests, it added.
In Saudi Arabia, those killed included a child offender aged 15 or 16 at the time of his detention, and an Egyptian man who was beheaded for "sorcery" and adultery - one of at least 76 foreigners executed by the Gulf kingdom.
Despite the statistics, Amnesty welcomed the wider trend toward the global abolition of the death penalty, noting that in December 2007 the UN General Assembly had voted by a large majority in favour of a resolution calling for an end to capital punishment.
"The taking of life by the state is one of the most drastic acts a government can undertake. We are urging all governments to follow the commitments made at the UN and abolish the death penalty once and for all," it added.