The will, due to be published next week, is thought to give three-quarters of her estate to her sons, Prince William and Prince Harry.
The Sun newspaper reports that each one of the godchildren - who are aged from 16 to 2 years - will be able to choose a personal item which had belonged to the Princess.
It says the original will, made six years ago, has been changed with a "posthumous amendment" to reflect her "love and care" for the godchildren.
The godchildren come from a variety of backgrounds and include the children of friends such as two-year-old Domenica Lawson and royalty such as Prince Philippos, the 11-year-old son of ex-King Constantine of Greece.
Diana's mother Francis Shand Kydd and sister Lady Sarah McCorquodale are executors of the estate.
The bulk of the estate comes from the Princess's divorce settlement, with the remainder from investments and her personal fortune.
Her butler, Paul Burrell, is expected to receive £50,000 made at the bequest of the Spencer family.
The Princess's children have already chosen personal items and family possessions which they will keep.
Diana memorial concert
The details of a celebrity concert in memory of Diana, Princess of Wales will be released on Friday.
The Spencer family will announce the line-up for the concert which is to be staged in the grounds of Althorp Park in Northamptonshire, where the Princess is buried on a small island in an ornamental lake.
Sir Cliff Richard, Chris de Burgh and opera star Dame Kiri Te Kanawa are among those expected to take part.
But Sir Elton John - who sang a rewritten version of Candle In the Wind at the princess's funeral - is not expected to be there because of concert commitments elsewhere.
Fifteen-thousand tickets will be available for the open-air event in the deer park on the estate on Saturday June 27 - four days before what would have been the princess's 37th birthday.
They will go on sale from 10am on February 28.
Profits from the concert are to be donated to the Diana Memorial Fund.
The battle for Diana's lucrative legacy
(25 Feb 98 | Special Report)
Diana fund to set up new Web site and US office
(22 Feb 98 | Sci/Tech)
The BBC's Diana Archive
Buckingham Palace's Diana Site
The British Monarchy
Althorp House
The BBC is not responsible for the content of external internet sites.
Authors revolt over book ban
Thousands expected for countryside march
Stars line up for Diana memorial concert
Finally gone - Windsors auction raises £14m
Queen backs historic change to who may rule
Final call for gun owners
Outspoken army major faces sack
Paratrooper's murder conviction quashed
Oxbridge escapes cuts in grants
Last chance to spend old 50ps
Ban on media cash for witnesses
No ticket, don't travel - Straw
(From Sport)
Clapton helps to 'kick them blues'
Government reassurance on MMR vaccine
North battered by gales
World Court claims authority in Lockerbie dispute
Mothers win sacking cases
Patten sues over scrapped book deal
Unionists issue talks warning
British journalist "unlawfully killed" in Chile
England's past looks into future
(From Sci/Tech)
Regions get bigger share of Millennium millions
Rural anger goes to town
Silver Seraph rolls into limelight
(From Business)