The first phase of the redevelopment includes a redesign of the hotel's 153 bedrooms, an open-plan foyer leading into the RBG Bar & Grill and an improvement of its leisure club, gym and spa.
Following its completion, Carlson Rezidor is overhauling the venue's conference and events facilities. The largest suite will host events for up to 475 delegates.
The refurbishment is part of a £40m investment across the group's 24 hotels in the UK and Ireland.
Sarah Dainty, Park Inn by Radisson Telford's sales manager, said: "As one of the company's flagship hotels, the Park Inn by Radisson in Telford attracts delegates from across the UK business market.
The mammoth investment in the venue demonstrates Carlson Rezidor's continued commitment to the destination, and we very much look forward to welcoming business and leisure visitors, and giving them the opportunity to see for themselves just what we have to offer."