He outlined his plan to give everyone in Scotland a say during a speech in Campbeltown, Argyll, where he held a cabinet meeting with his key ministerial team.
“The process of drawing up a constitution in itself will energise and inspire people,” he said.
“It will provide us with a chance to reflect on the democracy and society we want to live in, the values that we most cherish.
“Independence offers the opportunity for Scotland to move away from that outdated and profoundly undemocratic Westminster system - one which for two-thirds of my life has delivered governments with no popular mandate in Scotland.
“We will move instead to a more transparent, democratic and effective system of government - a government of the people, by the people and for the people of Scotland.”
The UK is the only nation in the European Union or Commonwealth without a written constitution or Constitution Act, Mr Salmond said.
Assuming a Yes vote in the referendum in September next year, Mr Salmond said one of the most “exciting” tasks will be to draft a constitution.
“Since no single party or individual has a monopoly on good ideas, all parties and the people of Scotland will be encouraged to contribute to drawing up a constitution,” he will say.
“Modern countries use their constitutions to articulate their values, to define who they are.
“They don’t only protect human rights, they enhance liberties and define responsibilities. Scotland’s constitution will do the same.
“It will make clear that it will uphold the values, rights and responsibilities of the people, of the community of the realm of Scotland. By doing so, it will make a real difference to people’s lives.
“In all of this, we will adhere to one fundamental principle. In Scotland, the people are sovereign. Not the government, not the parliament, not even the monarch, but the people.”
Mr Salmond was in Campbeltown as part of a regular summer tour held by his cabinet each year.
Scottish Liberal Democrat leader Willie Rennie said: “Whilst I share Alex’s view that we need a written constitution to empower citizens, he overstates his case by branding the UK as profoundly undemocratic. The UK is not like North Korea nor China and he does his case no good by implying we are.
“Using the prospect of a written constitution as a vehicle to promise all things to all people does not help move the constitutional debate forwards.
“This simply reinforces the fact that the First Minister will say anything to everyone to achieve his independence plans.”
Scottish Conservative leader Ruth Davidson said: “I am not aware of any popular clamour for a written constitution because the unique way in which the United Kingdom is governed has provided not only a robust protection of rights but the ability to meet the challenges of ever-changing circumstances.
“As far as I can see, the only people who will be energised by the drawing up of a written constitution will be government lawyers and civil servants.”