The £10.5 million project envisages a four-storey building incorporating a 420-pupil replacement for Cabot Primary School, offices for city council staff and a new St Paul's Children's Centre.
It would be part of the proposed Dove Lane scheme being drawn up by the consortium of developers PG Enterprises and regeneration group Places for People.
In addition to the rooftop playground, the new primary school, to be built close to the existing school, would also have external play decks on each floor to maximise available space. There would also be more play space at ground level than at the existing school.
Councillor Derek Pickup said: "The building will have sustainable design features that will provide valuable opportunities for learning and will boost the life chances of hundreds of children in the St Paul's area of Bristol."