The region's parliament in January passed a 'declaration of sovereignty' which it said provided grounds for Catalonia "to exercise its right to decide" on its political future.
The national government rejects efforts by Catalonia's leaders for greater independence, fanned by the economic crisis which has turned Spain's richest region into its most indebted.
The central government said in a statement on Friday that the Catalan declaration was against the country's constitution, which guarantees "the indissoluble unity of the Spanish nation".
"The cabinet has passed an agreement setting out a legal challenge before the Constitutional Court against the Catalonian Parliament's measures that approve a declaration of sovereignty," it said.
Catalonia is home to 7.5 million of Spain's 47 million people. It accounts for more than a fifth of Spain's economic output and a quarter of its exports.
Proud of their distinct language and culture, many Catalans resent seeing their taxes redistributed to other regions of Spain at a time of recession and spending cuts.
The declaration said Catalonia would hold a popular consultation on its future after discussions with the Spanish state, European authorities and the international community.
Spain's Prime Minister Mariano Rajoy has criticized Catalonia's right-leaning regional president Artur Mas's campaign, calling for unity to overcome the economic crisis.
Mas, who has promised to hold a referendum in 2014, called the government's announcement on Friday "misplaced".
"If they appeal to the Constitutional Court against a democratic declaration by a parliament, that means they are not willing to hold a dialogue," he said.