China's then leader Deng Xiaoping opened the door to market liberalisation on December 18, 1978, endorsing small-scale private farming, the first step towards abandoning the late leader Mao Zedong's vision of communal agriculture and industry.
China's economy has since grown into the world's fourth-largest behind the US, Japan and Germany, and annual per capita income soared to about 19,000 yuan ($2,760) last year, up from just 380 yuan in 1978.
Separately, China announced on Thurday that it will dispatch naval ships to join international forces battling Somali pirates.
Liu Jianchao, the foreign ministry spokesman, said Beijing welcomed stronger international co-operation in countering piracy, which was why China decided to send vessels to help the cause.
"Now the preparation is under way," Liu said. He did not give details about the mission.
Amid the events marking Deng's historic liberalisation decision, China has been criticised for sentencing two people to death for attacks in the troubled Xinjiang province and for resuming blocks on websites after relaxing censorship for the Beijing Olympics.
A Chinese court sentenced two people to death for an attack that killed 17 people in the Xinjiang border region, state news agency Xinhua reported on Wednesday.
The attackers allegedly crashed a lorry into paramilitary police before detonating some explosives in the city of Kashgar in August.
Abdurahman Azat, 33, and Kurbanjan Hemit, 28, said to be residents of Kashgar, were convicted of intentional homicide and illegally producing guns, ammunition and explosives by the Intermediate People's Court of Kashgar, Xinhua said.
Fifteen people were wounded in the attack, which took place a few days before the start of the Olympics.
China has also been criticised this week for allegedly censoring websites in a U-turn on earlier promises to expand media freedoms in the run-up to the Olympics.
Beijing on Wednesday defended its right to block websites it deems to have broken its laws, such as by recognising "two Chinas" - a reference to self-ruled Taiwan which Beijing claims sovereignty over.
The Chinese-language websites of the British Broadcasting Corporation and Voice of America, along with the Hong Kong-based media Ming Pao and Asiaweek, are among sites that have been inaccessible in China since early December, according to Reporters Without Borders.
|China had relaxed internet access and media freedoms during the Olympics [EPA]
"Right now, the authorities are gradually rolling back all the progress made in the run-up to the Olympic games, when even foreign websites in Mandarin were made accessible.
The pretence of liberalisation is now over," the group said in a statement on Wednesday.
Despite dramatic economic changes, however, the political system remains strictly controlled by the Communist party and dissent is seldom tolerated.
On Wednesday, the European parliament awarded the human rights Sakharov prize to jailed Chinese dissent Hu Jia, known for his campaign for civil rights, the environment and Aids victims.
Hu was arrested last year after giving testimony on human rights in China to a European parliamentary committee on human rights via video-conference.
He is now serving a three-and-a-half year prison sentence for subversion.
Hu's nomination for the prize angered Chinese authorities and Beijing had warned European legislators of damaged ties if they went ahead with awarding Hu the prize.