Trump, 77, won 60 percent of support among registered Republicans polled by the University of North Florida, while DeSantis could only claim 21 percent.
Vivek Ramaswamy, the millionaire entrepreneur and political newcomer whose star has burned brightly but now seems to be fading, won one percent.
The pollsters surveyed 788 people between October 23 and November 4.
Ron DeSantis (left) is now significantly behind his rival Donald Trump in the polls
When Trump and DeSantis were head-to-head, 59 percent of respondents said they would vote for Trump, with 29 percent for DeSantis.
The survey is deeply troubling for DeSantis, said Dr Michael Binder, director of the university’s Public Opinion Research Lab.
‘Despite historically high approval in the polls, Governor DeSantis losing steam in his home state doesn’t bode well for his national campaign,’ said Binder.
‘Even if you wipe out the rest of the competition in a head-to-head, Trump leads DeSantis by 20 points.’
Trump trumpeted the new poll on his Truth Social account, posting a graphic showing his lead over the man he has nicknamed ‘DeSanctimonious’.
The Florida respondents were also asked about their feelings regarding Trump’s actions following the 2020 election.
Well over two thirds – 71 percent – said they agreed with the statement that ‘he was just exercising his right to contest the election.’
DeSantis, Vivek Ramaswamy and Nikki Haley are seen in Des Moines, Iowa, on Friday
DeSantis was widely assumed to be the natural Republican leader, but has failed to find his footing. He is seen with his wife Casey on November 8
Only 16 percent said they aligned more with the statement, ‘he went so far that he threatened American democracy.’
Binder said their response did not surprise him, and tallied with their overall support for Trump as their nominee.
‘Given the support for Trump in the upcoming election, it’s not surprising that most of these voters think he was within his rights to contest the election,’ said Binder.
‘Interestingly, the 16% who think he threatened democracy tend to favor DeSantis narrowly over Nikki Haley.’