In his annual address to the National People's Congress (NPC) in Beijing's Soviet-era Great Hall of the People, Wen Jiabao also pledged to keep the world's seventh largest economy growing without overheating.
The 3000 NPC delegates peppered Wen's two-hour speech with applause, clapping loudest when he appealed for national unity, signalling their approval for the law that could prove the legal basis for an attack on Taiwan.
"This law represents the common will and strong determination of the entire Chinese people to safeguard the sovereignty and territorial integrity of the country and never allow secessionist forces working for 'Taiwan independence' to separate Taiwan from China under any name or by any means," Wen said.
Beijing has claimed sovereignty over the offshore island of 23 million since the end of China's civil war in 1949, when the defeated Nationalists fled there from the Communist-held mainland.
China has threatened to attack if Taiwan formally declares independence, and will boost defence spending by more than 12% this year in order to back up that pledge.