It includes a new entrance and reception leading to an open plan bar and revamped restaurant.
The four-star hotel is owned by Manchester-based brewer JW Lees and is housed inside a former 19th Century country house.
William Lees-Jones, managing director of JW Lees said: “Opening the new bar and restaurant at Alderley Edge Hotel is our first major investment in our 190th year.
“Alderley Edge Hotel is our most prized asset and it is our aim to be best in class, with a flagship hotel that we can be very proud of.
“JW Lees is a lot more than a just a brewery and our investment in hotels and inns continued to grow with major developments planned for 2018.”
The 3 AA rosette restaurant has replaced tasting menus with a full menu of classic dishes including steak and ox cheek suet pudding (£15.50), lightly battered sole goujons, chips and peas (£16) and open corn fed chicken pie with brown butter mash (£17).
General manager John Scott added: “Our challenge is to realise the vision of the Lees-Jones family, who own Alderley Edge Hotel and to reinforce the hotel as the best boutique hotel in Cheshire.
“It’s not just about the décor and services but we are aiming to create a modern and welcoming space for people to escape, relax and enjoy beautiful food and drink. It’s a fantastic evolution that has evolved over the 30 years since JW Lees first acquired the hotel.”