The ten-month improvement project will see new approach lanes and traffic signals installed at Holdingham Roundabout.
Works are expected to start on Monday 15 February, subject to suitable weather.
Cllr Richard Davies, executive member for highways, said: "Following on from our successful improvement scheme at the A17/A153 Sleaford Rugby Club junction, we're just one month away from starting work at Holdingham Roundabout – the second half of these crucial Sleaford highway improvements.
"As part of the project, we'll be working to install additional lanes at each approach to Holdingham Roundabout, along with installing traffic signals at most of the entries onto the roundabout. These changes will not only help ease congestion here, but they will also improve safety for everyone using the roundabout."
As part of the work, drivers can expect a combination of 24/7 narrowed lanes and lane closures, along with a series of night-time temporary traffic signals, full road and roundabout closures as and when needed.
A temporary 30mph speed limit will also be in place when approaching and exiting the roundabout from all directions throughout the entire project.
In February, a westbound night-time road closure on the A17 East (towards Holdingham Roundabout) will be in place for two evenings, from 9pm to 5:30am, starting on Monday 22 February (subject to suitable weather).
The diversion route will be via the A52 westbound and the A15 northbound, and vice versa.
Cllr Davies added: "Holdingham Roundabout is one of the county's busiest junctions, so there will inevitably be some disruption while we carry out these improvements.
"We expect to have this whole project finished in December, ahead of the Christmas period. However, we'll be doing everything we can to have them finished sooner – but that will rely on the weather cooperating and us not experiencing any unexpected delays once we break ground."
Pat Doody, Chair of the Greater Lincolnshire Local Enterprise Partnership, said: "The Holdingham Roundabout upgrade is the second of two key strategic junction improvements in Sleaford supported in 2020/21 by the Greater Lincolnshire LEP which have a critical role to play in unlocking future growth potential in the town.
"Our £1.1m contribution towards this project will enable Sustainable Urban Extension delivery in the area to be realised, ultimately resulting in the creation of over 4,000 new homes.
Cllr Richard Wright, Leader of North Kesteven District Council, said: “Together with the successful works at the rugby club junction, the Holdingham roundabout scheme is critical to freeing up traffic flows, both for Sleaford and the wider network.
"Not only will this be good for Sleaford, the district and the broader county’s economic position by encouraging people and businesses into the town, but also for enhancing quality of life and environmental gain by relieving congestion which impacts on air quality and people’s use of time.
"Freeing traffic flow is equally beneficial in releasing the full commercial potential of the district council’s new economic growth area at Sleaford Moor Enterprise Park, as well as opening up broader economic regeneration and highways safety aspirations for the town.”
The £8.25m A17/A153 Rugby Club Junction / A17 Holdingham Roundabout scheme is being funded by the Greater Lincolnshire Local Enterprise Partnership, North Kesteven District Council, Lincolnshire County Council and developer contributions.
For more information about this and other major highways projects, visit www.lincolnshire.gov.uk/majorprojects.