"The whole situation [in China] is shrouded in secrecy and the numbers might well be much, much higher," Irene Khan, Amnesty's secretary general, said.
The survey found China, Iran, Saudi Arabia, Pakistan and the United States were responsible for over 90 per cent of the global total.
The organisation reiterated its call for countries to abolish the death sentence, describing capital punishment as a "legalised process of physical and psychological terror".
"The death penalty is the ultimate cruel, inhuman and degrading punishment. Beheadings, electrocutions, hangings, lethal injections, shootings and stonings have no place in the 21st century," Khan said.
Amnesty highlighted concern over Iran, saying the country "continued to execute prisoners who were under 18 at the time of the alleged offence, in flagrant violation of international law".
The organisation also called on Belarus, the only European nation to still use the death penalty, to end its practice.
"The Belarussian authorities must immediately declare a moratorium on death sentences and executions with a view to abolishing the death penalty completely," a separate report released on Tuesday said.
"The death penalty is the ultimate cruel, inhuman and degrading punishment. Beheadings, electrocutions, hangings, lethal injections, shootings and stonings have no place in the 21st century"
Iren Khan, Amnesty International secretary general
Amnesty International has estimates that around 400 people have been executed in Belarus since 1991.
"The whole process of the death penalty is shrouded in secrecy, prisoners and their relatives are not informed about the date of the execution, the body is not given to the relatives and they are not told where the burial place is," Amnesty said.
But the group also noted the world is moving a step closer to full abolition of the death penalty, with only 25 of the 59 countries that use capital punishment reported to have executed people in 2008.
"The good news is that executions are only carried out by a small number of countries, which shows that we are moving closer to a death-penalty free world," Khan said.
It also revealed that the number of people executed in the US last year - 37 - was the lowest since 1995.
"There is increasing evidence that the USA itself is slowly turning away from the death penalty," Amnesty said.