The collection at Althorp House features more than 150 personal objects including her Emanuel wedding dress.
A spokesman for Earl Spencer said it had been a "celebration" marking Diana's "charitable works and glamour".
Having raised more than £1.2m to help disadvantaged people around the world, it will close in August 2014.
The spokesman added: "The exhibition has been admired by thousands of people around the world and has been a wonderfully tasteful celebration of the late Diana, Princess of Wales's life and achievements."
Born Diana Spencer, at Park House near Sandringham, Norfolk, in July 1961, she became Lady Diana Spencer after her father inherited the title of Earl Spencer in 1975.
Diana moved to Althorp House in 1976 and was said to love the grounds and house, which was bought by Sir John Spencer in 1508.
The exhibition, which opens to the public throughout July and August, opened on 1 July 1998, which would have been her 37th birthday.
Following her death in a car crash in Paris in 1997, Diana's remains rest on an island in an ornamental lake known as The Oval within the grounds of the Althorp estate.
An exhibition chronicling the life of Princess Diana, based at the Spencer family's Northamptonshire home since 1998, is set to close next year.