Mr Rennie wants to amend the Criminal Justice (Scotland) Bill, to scrap the practice, following concerns over increases in its use.
The change could mean all stop and searches would be underpinned by legislation and would require reasonable suspicion of criminal activity.
At present, over 70% of stop and searches are voluntary. These are also required to be "intelligence-led, proportionate and respectful", according to the Scottish Police Authority, but officers do not have to meet certain legal requirements.
The amendments would "put stop and search on a regulated footing", Mr Rennie said at the Scottish party's conference in Aberdeen. This would "keep the police focused on those they suspect of crime and confirm the freedoms of the innocent", he added.
"No liberal party would act like this government. No liberal party would take a wrecking ball to the justice system like they have."
Mr Rennie last week accused Alex Salmond of being "complacent" about a fourfold rise in the use of stop and search. Some 519,213 stop and searches were conducted between April and December 2013.