Here are some major events in the Party's history:
July 1, 1921 - Communist Party of China founded in Shanghai.
1927 - Nationalist leader Chiang Kai-shek launches attacks on Communist strongholds in Shanghai, killing hundreds of activists, after party launches a failed uprising. The party retreats, going underground and decamping to the countryside.
1934-35 - Mao Zedong begins ascent to power during the Long March, a series of retreats by the Red Army to evade Chiang's pursuing Nationalist forces.
1936 - Japan expands occupation of northeast China, the Nationalists join fragile "united front" with Communists to defend against the common threat. At the end of World War Two, the Nationalist-Communist civil war resumes.
Oct 1, 1949 - Mao Zedong proclaims the establishment of the People's Republic of China. Chiang Kai-shek and the defeated nationalists flee to Taiwan by late in year.
June 1950-July 1953 - China backs North Korea in Korean War against US-backed South Korea.
1953-57 - China makes "transition to socialism", nationalising industry and putting farmland under collective control, with economic development helped by Soviet aid.
1957 - Anti-Rightist Movement purges intellectuals and liberal reformers, whom Mao earlier urged to speak out and criticise the party's errors.
1958 - Mao launches his "Great Leap Forward," a campaign to catapult China into advanced socialism by massively increasing industrial and farm output through collectivisation. The plan collapses and brings widespread famine by 1961 that killed 30 million people by some expert estimates.
1961 - Relations with the Soviet Union deteriorate over Cold War policy and ideological disputes. China denounces Soviet leadership of the Communist bloc.
1966-76 - Mao, fearing that his revolutionary achievements will be betrayed by compromise and "capitalist restoration", launches the Cultural Revolution, a violent campaign to rid the country of perceived ideological enemies, including senior Party officials.
Feb 1972 - US President Richard Nixon visits China, curtailing the confrontation between China and the United States that began after 1949.
Sep 1976 - Mao dies. His successor Hua Guofeng and other veteran officials engineer the arrest of the "Gang of Four," the group of officials who want to continue the radical line of the Cultural Revolution. Hua Guofeng acts as leader for a few years while Deng Xiaoping, purged during the Cultural Revolution, returns to power and comes to back reformist policies.
Dec 1978 - Party Central Committee holds "Third Plenum" meeting, marking the launch of reformist policies that eventually lead to the break of farm communes in favour of family-contract farms and other steps that develop into market reforms.
Jan 1979 - US and China reestablish diplomatic relations.
April-June 1989 - Students and workers protest for political reform and against corruption on Tiananmen Square in Beijing and also in other cities, before the army crushes the movement on June 4, killing hundreds.
1991-92 - Deng takes tour of southern China, accusing central officials of stalling and jeopardising economic reform and relaunching a new wave of market reforms.
March 1993 - Jiang Zemin becomes president.
Feb 1997 - Deng dies.
2002-2003 - Jiang Zemin retires as party chief and then president, opening way to the "fourth generation" headed by Hu Jintao.
July 1, 2011 - The party marks its 90-year anniversary.
2012 - The party will hold its 18th National Congress; Vice President Xi Jinping expected to be named Hu's successor.