China has threatened to impose the death penalty in what it calls extreme cases of "diehard" Taiwan independence separatism.
China views Taiwan as its own territory, and has made no secret of its dislike of newly elected Taiwanese President Lai Ching-te.
The new guidelines say China's courts, prosecutors, public and state security bodies should "severely punish Taiwan independence diehards for splitting the country and inciting secession crimes".
It adds Chinese institutions should "resolutely defend national sovereignty, unity and territorial integrity," according to China's state-run news agency.
That is despite Chinese courts having no jurisdiction on the democratically governed island.
Sun Ping, an official from China's Ministry of Public Security, told reporters in Beijing the maximum penalty for the "crime of secession" was the death penalty.
"The sharp sword of legal action will always hang high," she said.
Taiwan's Mainland Affairs Council on Friday slammed Beijing's move, urging its people not to be threatened by China.
"The Beijing authorities have absolutely no jurisdiction over Taiwan, and the Chinese communists' so-called laws and norms have no binding force on our people," it said in a statement.
"The government appeals to our country's people to feel at ease and not to be threatened or intimidated by the Chinese Communist Party."
The guidelines detail what is considered a crime worthy of punishment, including promoting Taiwan's entry to international organisations where statehood is a condition, having "external official exchanges" and "suppressing" parties, groups and people that promote "reunification".
The guidelines add a further clause to what could be considered a crime — "other acts that seek to separate Taiwan from China" — meaning the rules can be broadly interpreted.
Mr Lai has repeatedly offered to hold talks with China, but those offers have been rebuffed.
He says only Taiwan's people can decide their future.
Reuters