Designed by UK architects Tate Harmer, the 109-bedroom hotel will blend into the countryside and have high standards of accessibility, energy efficiency and sustainability.
Construction is planned to start in late 2017 and completed by April 2018.
The hotel had initially received planning permission in June 2015.
However, revised plans were submitted in May 2016 following advice from hotel experts.
These revised plans were then withdrawn after public concern about the visual impact and scale of the building.
The latest approved plans address these issues.
The unconventional design of the construction will incorporate timber poles and stone cladding with a meadow and orchard surrounding the building.
CGI image of the design
David Harland, Eden Project executive director, said: "Our ambition has always been to build a hotel at Eden, so we're pleased to have been granted planning permission.
“We feel that the hotel will be a positive addition to the already excellent accommodation available in our local area and will help bolster our reputation as an attractive venue for events, conferences and weddings.
"We feel the design is eye-catching, but in keeping with its surroundings, and we're proud to say that it will be built to the highest environmental standards."
Research from the Eden Project revealed that more than 18 million people have visited it since it opened in 2001, contributing £1.7bn to the Cornwall economy.
An estimated 35-40 jobs will be created by the new hotel.
Jerry Tate, a partner at Tate Harmer, said: “This building is a unique response to its local Cornish context and the philosophy of the Eden Project.
“Landscape is at the heart of the scheme, with local timber cladding and Cornish stone walls embedding the building into its setting.
“We are proud to have developed this design with the Eden Project as part of our ongoing relationship.”