The work would cost approximately £20m and, if approved, will be funded from the existing City Centre Masterplan budget, with a target completion date of autumn 2019.
The designs have been drawn up by award-winning landscape design consultancy LDA Design.
A consultation has been today launched on the planned overhaul.
It will run until Friday and residents are being asked to share their views by completing a survey.
Aberdeen City Council leader Jenny Laing, said: “I am delighted with the proposals that LDA Design has brought forward for Union Terrace Gardens as part of our City Centre Masterplan. LDA was tasked with improving access, amenity and activity while conserving UTG’s rich heritage – what residents asked for during a consultation on the masterplan itself.
“These proposals respect the unique character of the gardens while making the space more usable for all.
“I would urge all residents to share their views so the LDA can refine the design and ensure we get the best result for everyone.
“Union Terrace Gardens represents a glorious gift from the past and in turn can be our gift to future generations.
“It is ours to nurture.”
The designs come four years after previous plans for a Union Terrace Gardens update were shelved.
Granite Web, which featured two plazas and a cultural arts centre, was selected as the preferred design in January 2012 after a public referendum.
Oil tycoon Sir Ian Wood had offered to invest £50m in a scheme to create a street-level public square over the gardens.
But after Labour became the largest party in Aberdeen following local authority elections later that year, the council rejected the proposal and Sir Ian’s offer was withdrawn. Now, development of the gardens is back on the table.