Speaking in Catalan and French Mr Puigdemont He revealed he had travelled to Brussels to make the EU see the crisis as "a priority" and to show the aggressive behaviour from Spain, he added.
Defiant Puigdemont declared that Catalonia will not accept Article 155, which would "destroy" the region.
He added that ministers are working to make it impossible for Madrid to "dismantle Catalan institutions."
He railed against the "aggression and violence against millions of people who exercised their right to vote" in a scathing attack on Spain in front of journalists today.
He said "we've seen a very aggressive offensive against the Catalans".
He added the priority is no violence, saying: "You can't build a republic upon violence.
"Peace and dialogue are our priority."
He said the charges against him, of rebellion, sedition and misuse of public funds, are an example of the "extreme opression" from Madrid.
Calres Puigdemont speaking in Brussels today
Is Puigdemont SAFE IN EU? Catalan leader has no chance for asylum
Carles Puigdemont could flee Belgium in fears over Spanish extradition
Of the 21 December election, he said: "The 21 December elections called by the Spanish government are a democratic challenge and don't scare us.
“We will face this election and respect the results."
Slamming Madrid, he asked whether Spain too would respect the results.
Adding: "Problems are solved by voting and not by imprisoning politicians and citizens."
Speaking of the charges against him, he said: "Yesterday we saw the charge filings which confirm the extreme aggression of the Spanish government.
"The lawsuit doesn't stand up legally, it doesn't pursue a crime, it pursues an idea."
“We've travelled to make the Catalan problem clear in the heart of Europe and to denounce the absence of judicial impartiality."
Mr Puigdemont said he wants an EU reaction to Catalan independence
When asked if he was prepared to go to jail, he deferred to his ministers.
Minister for work Dolors Bassa said: "Would that be a fair outcome? There’s your answer."
She added that it would be "impossible" to have a fair trial in Spain.
Interior minister Joaquim Forn said: "We're convinced about everything we've done.
"The crime of rebellion is comparable to terrorism. We've never acted with violence.
"Puigdemont is requesting help from Europe because they're treating us as terrorists."
Mr Puigdemont is speaking in Brussels
Calling upon the Catalan people he said: "Be ready for a long process. Spain only understands strength."
In a message to world leaders he said: "I ask the international community to react.
"To allow the Spanish government to not negotiate means ending with the idea of Europe."
He also ruled out asylum from Belgium saying he was there as a European citizen, "I'm here to act with freedom and security.
"We have to work as a legitimate government. The best way to express ourselves is from the capital of Europe."
But said he did not know how long he planned to stay in Brussels, but said he was enjoying his freedom of movement afforded to him by being a European citizen.
He added that he was in constant contact with his ministers, and they were in Brussels "to work".
Catalonia LIVE pictures: Pro-unity protesters gather in Barcelona
Sun, October 29, 2017
Pro-unity protesters gather in Catalonia's capital Barcelona, two days after lawmakers voted to split the wealthy region from Spain, plunging the country into an unprecedented political crisis
1 of 16
A protester waves a pirate-shaped collage of a Catalan Flag during a pro-unity demonstration at Passeig de Gracia in Barcelona
He was speaking just one day after Spain’s state prosecutor called for him to face charges of rebellion, sedition and misuse of public funds.
Journalists in the room described it as "chaotic" as a couple of hundred reporters were crammed into a small room, and many left waiting outside.
Mr Puigdemont appeared at the press conference with Catalan minister for work Dolors Bassa, minister for health Toni Comín and Catalan MEP Ramon Tremosa.
Speaking outside his office in Flanders yesterday Mr Puigdemont's Belgian lawyer Paul Bekaert said Mr Puigdemont was considering seeking asylum in the country.
He said: "We have not yet decided yet. We have a lot of time to decide.
“We will see in the coming weeks what we are doing."
He added that the Catalan leader “didn’t run away from Barcelona” and had no intention of hiding in Belgium.
He insisted: “He is an EU citizen who has come to Brussels, maybe he has other political intentions when he comes to the European capital, but it is too early to talk about a diplomatic incident.”
Belgian migration minister Theo Francken described a political asylum request from Mr Puigdemont as "not unrealistic" and "100 per cent legal".
But Prime Minister Charles Michel appeared to quash suggestions by asking Mr Francken "not to fan the flames", and said an asylum request was "absolutely not on the agenda".
Protests have been sparked all over Catalonia
Mr Puigdemont and five former members of his cabinet fled in a car to Marseilles yesterday before flying to Brussels.
Mr Bekaert, specialised in extradition cases and political asylum, was also the lawyer of alleged ETA member Natividad Jáuregui, who fled to Ghent.
Belgium refused to extradite Mr Jáuregui to Spain after three arrest warrants issued by the National Court in 2004, 2005 and 2015.
Over in Madrid, Spanish premier Mariano Rajoy has called a Council of Ministers at 6pm to approve "organisational aspects" of the Catalan elections on December 21.
Minister of Public Works, Íñigo de la Serna this morning said that the main task after rate elections will be to “heal the wounds” caused by Mr Puigdemont.