The proposal is an alternative to relocation plans for a new £60m stadium at Ashton Vale which is facing a planning inquiry.
If the Aston Vale plan is turned down, Bristol Sport would redeveloped Aston Gate in stages over three years to increase the capacity to over 26,000 seats.
Ashton Gate could get a new look as a 26,000-seater stadium
The Wedlock and Williams stands would be demolished and new stands built in their place, while the Dolman and Atyeo stands will be renovated.
The plans will be presented to the local council for approval in the summer.