The rebuilding scheme, which is due to start on August 28, will see capacity increased to more than 17,000 from the current 15,358 with a new stand built on the Bridgford Road side of the ground.
Nottinghamshire also plan to install permanent floodlights.
"As a sporting venue of world renown, Trent Bridge is hugely important to the local economy and our partners recognise the need to help us do all we can to retain Test match status in the face of stiff competition from other parts of the country," Nottinghamshire chief executive Derek Brewer said of a scheme that has received financial support from several local authorities.
The Nottingham ground, situated near the River Trent in England's East Midlands, was staging its 54th Test on Friday having put on its first in 1899.
England, for much of the 20th Century, had six Test match venues - Lord's, The Oval, Trent Bridge, Headingley, Old Trafford and Edgbaston.
But in recent years Durham's Rose Bowl ground has joined the list and for the 2009 Ashes series Sophia Gardens in Cardiff, the home of Welsh county Glamorgan, is also set to stage its first Test. Meanwhile Hampshire are pushing their Rose Bowl home to become a Test ground.
With a maximum of seven Tests being staged in England since 2000, split between two touring sides, and with Lord's so far guaranteed two, this has led to increased competition between the remaining Test venues.