Keeping the progressive nature is the basic cause of the success of the Communist Party of China (CPC), said General Secretary of the CPC Central Committee Hu Jintao on Friday.

The reason why the Party can be the core force in leading the nation to the victory of revolution, construction and reform and why it can always stand fast in the international and domestic changes is that it always represents the development requirements of China's advanced social productive forces, the progressive course of China's advanced culture, and the fundamental interests of the majority of the Chinese people, said Hu, who is also Chinese President and Chairman of the Central Military Commission.

"It is also because the CPC always attaches great importance to maintaining and developing the progressive nature as a Marxist party," he said at a grand rally to mark the 85th founding anniversary of the CPC.

The 85 years of CPC's history is a history to pursue the independence, liberation and prosperity for the Chinese nation, and a history to achieve the freedom, democracy and happiness of the Chinese people, Hu said.

Enormous success has been achieved in the past 85 years by the CPC members, who devoted themselves in modern construction as well as in revolution times, he said.