In an interview with the Irish Times on Wednesday, Nicola Sturgeon said she sees the Northern Irish protocol on its border with Ireland as a template for Scottish independence.
But Mr Ross said the SNP had a “number of different policies”.
He said: “The SNP have a number of different policies, it seems, on the border, just in the most recent days.
“First of all, Nicola Sturgeon said that she hadn't heard one of her current MSPs, someone who's represented the south of Scotland for the last five years, say how good a border would be between Scotland and England.
"Nicola Sturgeon then said there would be no border between Scotland and England, and then she accepted that there would be a border, but that everything will be fine, without telling us how everything would be fine.”
Mr Ross added: "So I think we can see, yet again, the SNP have no answers to such a crucial point, for not just borders communities here, but for the while of for Scotland, in terms of creating a hard border between Scotland and the UK.
"Their plans for separation have not been thought through, and they have not been able to address the key concerns that people had during the referendum in 2014.
"Nothing that Nicola Sturgeon can say about this will change people's opinion that separating Scotland from the rest of the United Kingdom and creating a border between Scotland and England will have a massive detrimental impact on Scotland's trade with the United Kingdom.”
In an interview with the Irish Times earlier this week, Ms Sturgeon said replicating the Northern Ireland-Ireland border would allow Scotland to access the European Union, as well as the Common Travel Area.
She said: “The Northern Ireland protocol, if there are easements there, yes, I think that does offer some template, but we work in a proper planned way to make sure that any rules that have to be applied are applied in a way that absolutely minimises any practical difficulties for businesses trading across the England-Scotland border.
“Brexit had all been about narrowing Scotland’s horizons, in a trading sense, but also in terms of people. Independence is about opening up those horizons again and seeing Scotland firmly as a country playing its full part in Europe and the world.”
Ms Sturgeon added that she was confident that an independent Scotland would remain within the Common Travel Area, although that would require the agreement of Britain and Ireland and an opt-out from the EU’s Schengen open borders system.
She said: “There is nobody with any credibility anywhere that suggests that Scotland would not continue to be in the Common Travel Area. Even the scaremongers about independence so far haven’t tried to use [that] argument.
“And for people in Scotland, that’s a real win-win because we’d retain that freedom of movement across the Common Travel Area, but regain freedom of movement across the whole of the European Union. And so we’d be in the same position as the Republic of Ireland, which I think would be a really good position to be in.”