Vegetation clearance, archaeology and other preliminary works will begin ahead of breaking ground on phase three this spring.
The clearance works, which begin Monday 3 February, are expected to last for up to three weeks, subject to suitable weather.
Although most of the work will be carried out away from main roads, there may be some minor disruption on Whalebone Lane.
Cllr Richard Davies, executive member for highways, said: "As part of these early works, Galliford Try will be removing trees and other growth along the eastern section of the relief road route, which will link the A52 at Somerby Hill to the B1174 roundabout.
"Following this, a team of archaeologists will return to site and start investigating these areas ahead of us breaking ground on phase three this spring.
"Once we're officially on-site later this year, the most challenging part of phase three will be building the new rail bridge, which will not only span over the East Coast Main Line, but also the River Witham.
"Elsewhere on site, the team has finished building a widened section of A1 carriageway, allowing them to make a start on constructing the new bridged junction connecting the A1 to the B1174."
When built, the Grantham Southern Relief Road will stretch for 3.5km, linking the A52 at Somerby Hill to the A1.
The project is being led by Lincolnshire County Council and supported by South Kesteven District Council, Greater Lincolnshire LEP, Highways England, Homes and Communities Agency and local businesses.
For more information, visit www.lincolnshire.gov.uk/gsrr.