The roadshow will travel throughout Scotland to listen to the views of voters as the Lib Dems gear up to fight the 2016 Holyrood election in May next year.
The party will also use social media to gauge opinion, set up workshops for young activists and build a volunteer base for 2016.
The Lib Dems were reduced to just eight MPs across the UK at the general election, down from 57 in 2010.
Mr Rennie said: “At the general election we lost some of our great liberal giants. As leader of the Scottish Liberal Democrats I want to make sure we learn the lessons and heed the results.”
The Lib Dems have seen a surge in new members following the general election, reporting more than 10,000 since polling day.
“We will listen to the people of Scotland, to the people on the doorsteps and to the increasing numbers of people backing our party,” Mr Rennie added.
“As the Tory Government continues with its illiberal plans to curb our civil liberties and take the UK further to the right, the role of the Liberal Democrats is more important than ever.
“And in Scotland, the SNP has taken its eye off the ball on day to day public services. Their disregard for the voice of local communities and for liberal values continues to create divisions.
“All of this has created an even bigger space for Liberal Democrats to fill in the debate on what kind of country we want to be.
“Over the summer, we will undertake our biggest and most democratic listening exercise. Our policy roadshow will ensure that we hear the voices of the diverse communities across Scotland.
“For the new, young activists who have joined in their droves since polling day, I want to engage their fresh and ambitious ideas for our country’s future.
“We will listen to the people of Scotland, and we will demonstrate why Scotland needs strong liberal voices now more than ever.”