She began the fund on Wednesday morning to pay her fees after hiring star human rights lawyer Aamer Anwar to defend her case just hours before handing herself in to Scottish police.
Within four hours of starting the campaign it had reached above £100,000.
On Friday Ponsati was named along with four other former ministers in European Arrest Warrants issued by Spain's Supreme Court.
She was a minister in the Catalan government of Carles Puigdemont when it declared independence from the rest of Spain following an illegal referendum in October.
But she fled into exile in Scotland earlier this month, resuming a post as an economics research fellow at St Andrews University.
- The Puigdemont files: What you need to know about the case
- WATCH: Angry protest in Barcelona after ex-Catalan leader arrested
- Catalan separatists face rebellion charge as another key figure flees abroad
She was due to appear in court later on Wednesday for a preliminary extradition hearing where her lawyers will request that she be granted bail pending a full hearing.
In an appeal on the CrowdJustice site she wrote: : "The Spanish government issued a European Arrest Warrant to extradite me from Scotland and they will use all the resources at their disposal to fight this case.
"Judging the Spanish government by their past and present actions, if I return I believe I am likely to be subjected to degrading and inhumane treatment by the authorities."
She continued: “Over recent months the Spanish government stands accused of abusing the democratic process and the independence of its judiciary, whilst their Police with echoes of Francoism used brutal violent force to try and crush those who attempted to exercise their democratic right to vote.
"I am humbled by the tremendous support received from thousands of Scots and people across Europe," she wrote. "I am grateful for the solidarity of Nicola Sturgeon and the Scottish Government as well as politicians from across the political spectrum , but respect for the rule of law means that it is only right that your independent judiciary determines my fate.
Initially, she asked for £40k but after meeting the target within two hours, she upped the appeal to £100,000.
Anwar tweeted a thank you after hearing news that the fund had reached its target so quickly.
Thanku so much from @ClaraPonsati - ‘Defiant, Resolute & Determined to Fight Back' on way 2Edinburgh -Clara will b arrested in next hour & taken 2court 4extradition hearing at 2pm #DefendClara #Catalonia please keep sharing https://t.co/Lwi2rGLweG pic.twitter.com/XcMx6R8j5K— Aamer Anwar (@AamerAnwar) March 28, 2018
Spain's Supreme Court said it would prosecute 13 key separatists including Ponsati for "rebellion", a crime which carries a maximum penalty of 30 years in jail.
Puigdemont was arrested in Germany on Sunday where he in jail on remand pending the extradtion process.
Ponsati has received support from members of the Scottish National Party (SNP), which runs the devolved government in Edinburgh, which has condemned arrest warrants issued for the Catalan politicians.
However, First Minister Nicola Sturgeon has insisted she cannot intervene in an independent legal extradition process.
"It is well established that the Scottish government supports the right of the people of Catalonia to determine their own future and that we strongly oppose the Spanish government's decision to seek the arrest and imprisonment of independence-supporting politicians," she said in a statement.
To all those angered by latest developments on #Catalonia, please read @scotgov statement below. Our support for Catalan self determination and strong opposition to Spain's decision to seek the arrest and imprisonment of independence supporting politicians is well established 1/ pic.twitter.com/GIfgptAzqS— Nicola Sturgeon (@NicolaSturgeon) March 25, 2018