The former Scottish Conservatives leader claimed that any administration led by Jeremy Corbyn and reliant upon Nationalist votes would "disrespect the results" of both the 2014 independence vote and the 2016 Brexit referendum.
Ms Davidson, who unexpectedly stood down as the Tory leader north of the Border in August, said even an informal pact between Labour and the SNP would increase the chances of an IndyRef2 taking place.
Her intervention follows comments made by Boris Johnson that he would not allow a second independence vote as long as he was prime minister.
She continued: "In short, a Corbyn-Sturgeon political union would spell disaster for this country.
"Higher taxes, businesses punished, mass nationalisations, weaker defence, less safe streets and children born into the poorest households less able to change their life chances.
"And all of that with the country bitterly divided on constitutional lines with reruns of both major referendums. Jeremy Corbyn has spent his career taking sides against the UK, while Nicola Sturgeon has made breaking up Britain her life's work. A partnership like this would leave the country on its knees."
Earlier today, the SNP seized on remarks by the Secretary of State for Scotland, Alister Jack, that the SNP could win the right to hold an IndyRef2 in 2021.
The SNP said the gaffe proved that Mr Johnson's position on an independence vote was “unsustainable”.