Work on the second phase of St Giles Street improvements is set to start next Tuesday, June 21.
The section of road between Castilian Street and St Giles Square will be closed and traffic will be diverted south along Castilian Street onto Derngate.
The works follow on from an completed section between Hazelwood Road and Castilian Street.
Improvements including new paving, lighting and tree planting are expected to be complete before the Christmas shopping period.
Once the work is finished, a new road surface will be laid along the finished sections of St Giles Street.
Cllr Tim Hadland, Northampton Borough Council cabinet member for regeneration, enterprise and planning, said: “This is the latest phase in an extensive programme of improvements we’re carrying out across the town centre.
“It will enhance the environment for shoppers, and is fitting for a street which currently holds a Great British High Street winner title.
“Further phases are planned in St Giles Square and Fish Street, and these will be carried out in 2017.”