John Swinney expanded on plans to reintroduce a post-study visa, as outlined in the Scottish Government's White Paper on independence last month.
The plan would allow recent graduates to stay in the country to work or set up a business, retaining skilled and educated graduates as part of the labour force.
Every thousand extra graduates working in Scotland boosts the country's economy by an estimated £10 million and supports about 200 jobs, according to the Scottish Government.
Conservatives said that a significantly different immigration policy would require "some kind of border patrol".
Mr Swinney said: "We should be encouraging more talented people from around the world to further their education in Scotland, providing income for our education institutions and contributing to the local economy and community diversity."
"It is absurd that talented individuals are instead being discouraged from coming to Scotland. It's an out-of-date approach that is not fit for a modern country.
"Immigration policies decided in Westminster simply do not fit Scotland's needs, and they are hampering our ability to develop a thriving economy. We need to take steps to boost our working-age population, not measures that stop people from contributing."
Conservative MSP Alex Johnstone said: "This is another indication that the SNP wants to adopt a drastically different immigration policy than the rest of the UK. If that is the case, it is fairly clear that some kind of border patrol will have to be established in the event of separation.
"Why would the rest of the UK want to jeopardise its security just because Alex Salmond wants to go down a different route on immigration?
"It is naive for the Scottish Government to suggest, if policies like this are implemented, that the remaining UK would not view Scotland as a soft entry point for illegal immigrants."