After several hours of deliberation, the court accepted a lawsuit filed by the conservative central government against the resolution, which was passed by Catalonia's regional parliament on Monday.
Acceptance of the lawsuit means the motion is immediately suspended while the court considers legal arguments.
The regional government of Catalonia immediately vowed to push ahead with its secession process despite the court's ruling.
“The political will of the government of Catalonia is to go ahead with the content of the resolution,” the vice president of the Catalan government, Neus Munte, told a news conference.
The court also agreed with a request by the central government that it “personally” notify 21 Catalan leaders who have promoted the resolution of the consequences they could face if they ignore the court's orders.
Among those cited are Catalonia's outgoing president, Artur Mas, his cabinet and the president of the regional assembly, Carme Forcadell.
“If they disobey the suspension they could be charged with the crime of disobedience,” a judicial source said.
The resolution approved by separatist Catalan lawmakers calls on the regional assembly to start working on legislation within 30 days to create a separate social security system and treasury, with a view to completing independence in 18 months.
It has the backing of Mas' Together for Yes coalition and the smaller far-left separatist CUP party, which together won a majority in the Catalan parliament for the first time in a September 27th regional election.
While Catalan separatist parties won a majority of seats in the regional parliament in the polls, they failed to win a majority of all votes cast – a fact emphasised by the central government in Madrid.
Prime Minister Mariano Rajoy said the promoters of the Catalan resolution want to “put an end to democracy and the state of law, subjugate the rights and freedoms of all citizens and break up the unity of Spain.”
“I will not allow it and I have the backing of the majority of Spaniards,” he told a news conference following an emergency cabinet meeting held as he gears up for a December 20 general election.
The resolution declares that the parliament of Catalonia is “sovereign” and not subject to decisions made by Spanish institutions, including the Constitutional Court.
Catalonia, a region of 7.5 million people with its own language, accounts for a fifth of Spain's economic output, and already enjoys a large degree of autonomy in education, health and policing.
But it is insisting on even greater autonomy, particularly where taxation is concerned, estimating that it gives more to the central government than it receives.
A 2010 decision by Spain's Constitutional Court to water down a 2006 statute giving the region more powers has added to the growing pressure for secession.
Rajoy met earlier on Wednesday with the head of the main opposition Socialists, Pedro Sanchez, who reiterated that he backed the prime minister in his defence of “the constitution and legality”.
But at the same time he accused Rajoy's government of “inaction” in the face of the separatist challenge and reiterated his call for a reform of the constitution to make Spain a federal state as a way to meet Catalonia's demands for more autonomy.
While the government prepared its lawsuit, public prosecutors released an 11-page report that said the promoters of the Catalan resolution could face criminal charges of “sedition” and “disobedience”.
The report said that those found guilty of sedition could be face a jail term of up to 15 years.
Catalonia tried to hold an official referendum on independence last year, but the Constitutional Court ruled it was against the constitution, arguing that all Spanish people have the right to decide on matters of sovereignty.
The region pressed ahead anyway and held a symbolic vote. Over 80 percent of the participants (2.3 million) voted in favour of independence.
By Michaela Cancela-Kieffer, with Daniel Bosque in Barcelona