Speaking on the 140th anniversary of the birth of Sun Yat-sen, the father of the revolution that toppled the last emperor in 1911, Hu said China also firmly opposed any separatist activities in Taiwan.
China should ''realise the complete unification of China as the fundamental interest of the Chinese nation and the sacred responsibility of the sons and daughters of the country,'' he told a gathering of around 3,000 people.
Sun was also the founder of the Nationalists, who were driven decades later into exile in Taiwan, after China's ruling Communist Party won a civil war in 1949.
Since then, Beijing has regarded Taiwan as a rebel province which must be brought into the fold, by force if necessary.
Relations between Beijing and the island have been volatile under the leadership of Taiwan President Chen Shui-bian.
Chen, who has twice won elections campaigning for formal independence from China, is not due to leave office until 2008. The Nationalists, or the Kuomintang, remain the main opposition party in Taiwan.