Nigel Farage, the party leader, will join Arthur Misty Thackery, the Scottish party chairman, and David Coburn, its Scottish MEP, and elected Ukip members from around the UK for the rally on September 12. The location is being withheld for security reasons.
In May 2013, Mr Farage was evacuated from an Edinburgh pub in a police riot van after Radical Independence and anti-Ukip protesters barricaded him inside.
Mr Thackery said: "This rally is to show the UK is one single united country and we have our fellow Scots and Britons all over the UK who want us to stay together."
Alex Salmond said: "If Mr Farage comes in a blaze of publicity in the next few days, as he says he's going to do, ignore him, he will go back to Clacton very soon."
SNP colleague, MSP Aileen McLeod, described Mr Farage's Scottish campaign as a "huge embarrassment and blow" to the No camp.
But Better Together insisted: "Ukip have no part to play in our campaign. We are campaigning against Nationalist politics of division and grievance."
l Ukip leader Nigel Farage said a by-election win for his party in Clacton would signal a "landslide in British politics" after a poll yesterday gave the party a massive 44 point lead over David Cameron's party in the seaside Essex constituency.