The comments came two days after Ma Ying-jeou took office in Taiwan
China and Taiwan are working to resume dialogue and have a rare opportunity to improve relations, a senior Chinese official has said.
In a speech, Beijing's top official for Taiwan, Chen Yunlin, said there had been "major positive changes" in the situation in Taiwan.
His comments came two days after a new president took office in Taiwan.
Ma Ying-jeou wants better ties with China and has called for a "new chapter of peace" between the two sides.
His predecessor, Chen Shui-bian, had angered China with moves towards formal independence, and relations had been severely strained.
In a speech reported by Xinhua news agency, the Chinese official said both sides were working to restart dialogue.
"Currently, good developing momentum is emerging in cross-strait relations, bringing a rare and important opportunity," Chen Yunlin said.
China respected the "desire of Taiwan compatriots to be masters of their own destiny", he said, but would continue to oppose "splittist activities".
The two sides should "establish mutual trust, set aside disputes and differences and create a win-win", he added.
On Tuesday Ma Ying-jeou said that maintaining cross-strait peace and prosperity was his goal.
The 57-year-old comfortably won the presidential election in March on a platform of improving economic ties with China.
But he has ruled out any negotiations on unification with Beijing while he is in office.
China says that Taiwan is part of its territory, although the two have been separately governed since 1949.