Alex Salmond has resorted to the "last refuge of every shameless populist" by making a string of pledges before next year's referendum.
But the SNP leader has failed to provide "any explanation" of how to pay for promises such as scrapping the so-called bedroom tax if Scotland becomes independent.
The Scottish Tory leader hit out as she addressed the UK Conservatives' annual conference in Manchester.
She told party activists that the referendum decision "affects each and every one of you, no matter where you live".
When Mr Salmond said "things designed to get right up your nose" they should know that "he doesn't speak for the majority of Scots", Miss Davidson said.
The First Minister is "the one talking Britain down and saying that Scots are desperate to leave" the UK.
"When it comes to this issue, Alex Salmond doesn't speak for a majority of Scots. In fact, he never has. Time after time, poll after poll, people in Scotland say they want to stay."
The SNP leader's new referendum campaign tactic is to "promise things for free" to voters.
"His new tack is the last refuge of every shameless populist in history staring down the barrel of defeat," Miss Davidson said.
"A quick tally shows, with 11 months still to go, at least £32 billion of uncosted promises. Under his independent utopia, Alex Salmond promises to increase overseas aid, reverse benefit reforms, underwrite oil decommissioning, set up a Scottish spy service, subsidise more wind farms and renationalise the Royal Mail. By polling day, I'm expecting free beer for every voter.
"All of these promises made to people in Scotland. None of them with any explanation of how they would be paid for."
It is "this say anything, do anything, promise anything approach to breaking up Britain" that those opposed to independence are campaigning against.
Miss Davidson began her address by telling delegates that, with the independence referendum next September, "this could be your last-ever UK party conference".
The ballot will be a "huge decision" which will touch "every one of our great British institutions".
She said: "This decision isn't the same as an election. If we don't like the result, we can't just come back in five years' time and vote again. It is a choice that is vital and is binding."
Anti-independence campaigners "have a lot of work to do to hammer home to people just how much Scotland gains from being part of the UK and how much the United Kingdom benefits from Scotland as a member".
Ms Davidson insisted: "Everyone in the UK benefits from our borderless Union. Scotland exports more to the rest of the UK than it does to the rest of the world combined. And, in return, we buy back too. In fact, we import more than twice as many goods by value from the rest of Britain than the rest of the globe.
"Tens of billions of pounds and hundreds of thousands of jobs rely on our shared market and cross-border flow. It's not just goods and finance criss-crossing north and south. It's people too."
Around 800,000 Scots live and work in other parts of the UK and more than 400,000 people who live in Scotland were born in England, Wales or Northern Ireland.
"Over the years we have worked together and fought together. We have mixed our families together. We are not easily separated by those who now seek to divide us," she said.
The UK is "stronger together, safer together", she said as she argued that Britain's "integrated Armed Forces" help to "keep our people safe at home and to work for peace abroad".
If Scotland leaves the UK, the nation's military hardware would have to be divided up like a "feuding couple" sorting out their assets after a split, according to Miss Davidson.
"Can you imagine this time next year if there's a Yes vote, trying to pick apart different divisions, splitting up regiments, dividing our nation's military hardware, our frigates and fighter jets, arms and artillery like a feuding couple dividing up their furniture?"
She concluded: "I am proud of the Britain that we've built together. And I will fight heart, mind, body and soul to keep it together."