The £61m project involves building a flyover to separate local and commuter traffic at the locally-known TGI island near Binley.
Main construction work is scheduled to start in the autumn, with the junction expected to open in 2022.
Highways England Programme Leader, Anita Prashar said: “The A46 is an important strategic route in the Midlands, connecting Coventry and Warwickshire to the motorway network.
“Upgrading the junction at Binley will help make everyday journeys easier and more reliable and we welcome the Secretary of State’s go-ahead for the improvement.”
Simon Statham, Head of Technical Programmes, at Midlands Connect said: “The A46 is one of the country’s most important trade routes.
“The junction at Binley Woods has become a major bottleneck, holding back logistics firms that rely on the A46, and major manufacturers located along the corridor.