The garden will be created by designer Marcus Barnett, a previous medal-winner at Chelsea. The design will be inspired by plants used in science and industry and will include foxgloves, geraniums, salvias and roses, each chosen for their medicinal or cosmetic uses.
The centrepiece will be a pavilion based on Kew's heritage buildings. Sussex-based landscape gardening firm The Outdoor Room will build the garden, which will be relocated to Kew Gardens after the show.
RBG, Kew director Professor Stephen Hopper said: "As an organisation, the future and security of the planet's plants is very close to our heart.
"We are truly honoured to have been given this platform at one of the most celebrated horticultural events in the world, from which we can exhibit a selection of plants that help and contribute to science and to our lives in general."