Mr Xi said "achieving total unity" was the "collective hope of all Chinese people" and any attempts to divide it were "doomed to fail".
In an address to China's nearly 3,000-member national parliament, Xi said China had the capabilities to stop any attempt to formalize the democratically ruled island's independence. But China's opposition to a United Nations ban on Pakistani terrorist and JeM chief Maulana Masood Azhar, who plotted terror attacks at bases of Indian armed forces, has also strained their relations.
Xi at the closing session of the National People's Congress reiterated China's approach of seeking peaceful unification with the island.
Western media reports have said that Xi's ultimate goal is believed to be disseminating his political thought around the world.
"China's development does not pose a threat to any country", Xi said.
China's longer-than-usual, 16-day legislative session had earlier approved a range of new appointments, including that of key Xi ally Wang Qishan as vice president.
Xi Jinping became president in 2013 and now looks likely to lead China indefinitely, after the National People's Congress (NPC) - a rubber-stamp parliamentary session that meets once a year - voted to remove a two-term limit on the presidency from the constitution.
The Global Times, an influential tabloid affiliated with the Communist Party, suggested Beijing wants Xi's thought to spread across the globe, criticizing Western values based on democracy and capitalism.
Nidahas Trophy 2018: Rohit Sharma praises 'fearless' Bangladesh
It is not every day that you get a chance to beat India. "It can happen to anyone when you bowl those big overs". Speaking to the media, a BCB spokesperson said,"Defeat is not a problem, we know that it is part of the game".
The comments of openness come as the threat of a global trade war looms with the U.S. imposing tariffs on steel and aluminum and reports Trump may target Chinese products specifically in future tariffs.
"Luckily China has maintained its steady rise for a long period".
Xi has emerged as the most powerful leader in China after Mao Zedong.
China's apparent readiness to expand its influence in the region has its smaller neighbors concerned.
His country wants to build a community with a shared future for mankind, promote economic globalization and free trade, promote connectivity under the Belt and Road Initiative and promote the win-win cooperation.
"These separatist actions will be met with the condemnation of the people and punishment of the history", he said.
In a visit likely to further irritate China, US Deputy Assistant Secretary of State Alex Wong will be in Taiwan this week, the island's foreign ministry said.
Malcolm Cook, a senior fellow at the ISEAS-Yusof Ishak Institute in Singapore, said, "Some Southeast Asian states have already bent to Chinese pressure".
The Chinese leader underscored on China's historic achievements, such as the invention of paper, the founding of Confucianism, building of the Great Wall of China and the country's experience of invasion "from outside and defending the national independence and freedom".