Scottish Conservative leader Russell Findlay says John Swinney's "idiotic" plans to cap the price of food would be a hammer blow for small retailers.
Findlay made the call during a visit to an award-winning, family-owned convenience store in Edinburgh.
The SNP's manifesto pledges to cap the costs of between 20 and 50 everyday items sold in large supermarkets.
However, the proposals have been slammed, with the Scottish Retail Consortium describing it as a "potty gimmick".
The Scottish Grocers Federation said the policy would threaten both the "viability and the benefits small local shops provide" as they struggled to match the prices in large supermarkets.
Findlay says Swinney's plan is a "desperate attempt" to distract from the SNP's lies, sleaze, waste and incompetence by picking a fight with the UK Government.
Sue Webber, the party's candidate for Edinburgh South Western, said that stores such as this one in Oxgangs are the "lifeblood" of local communities and the price cap plans will put jobs at risk.
Scottish Conservative leader Russell Findlay said: "John Swinney must know that his idiotic plan to dictate prices to supermarkets is unworkable nonsense.
"It would cripple small retailers, harm Scotland's farmers and would not reduce a single shopping bill.
"John Swinney's 1970s-era wheeze is a desperate attempt to distract from the SNP's litany of lies, sleaze, waste and incompetence.
"It's a dishonest ruse to pick a fight with the UK government - not a sincere attempt to help hard-working Scots.
"If John Swinney really wanted to help Scots with the cost-of-living crisis, then he would not be hammering them with the highest taxes in the entire UK.
"But if the SNP win the election outright, they will only put up taxes again. That is why you must vote Scottish Conservative on your peach ballot paper to stop an SNP majority."
Scottish Conservative candidate for Edinburgh South Western Sue Webber said: "Shops like this award-winning convenience store are the lifeblood of communities across Edinburgh.
"Yet John Swinney wants to put their future at risk with his ill-thought-out plans that are not deliverable in reality.
"The Scottish Conservatives will always stand up for small businesses which are already struggling thanks to the SNP's anti-business agenda. That is why in Edinburgh, and across Scotland, voters should back us on the peach ballot on May 7th."