Zhang Mingqing, vice- chairman of China's Association for Relations Across the Taiwan Strait, was visiting Taiwan as part of an academic symposium. Protesters surrounded and attacked Mr Zhang while he was sightseeing at a Confucian temple with minimal police protection. One protester jumped on to Mr Zhang's car when he tried to escape.
The attack comes at a sensitive time for cross-strait relations because Mr Zhang's superior, Chen Yunlin, is due to visit Taiwan within the next few weeks. Mr Chen would be the highest-ranking Chinese official to ever visit Taiwan and his presence would represent the first formal negotiations between the two sides in a decade.
Relations between Beijing and Taipei have warmed since May, when Ma Ying-jeou, the candidate of the nationalist Kuomintang party, succeeded the independence-minded Chen Shui-bian of the Democratic Progressive party, to become a democratically elected president of Taiwan.