The ruling in Edinburgh bans any of Wendy Berry's book, The Housekeeper's Story, from appearing in the Sunday Mail.
The book was subject to a court order in January 1995 which banned its publication throughout the world.
And Miss Berry, 70, risked arrest by flouting the order and selling 100,000 copies in the US.
She spent five years in exile, living in Canada and Ireland.
In October 2000, the Prince of Wales pardoned Berry and the grandmother from Merseyside returned to England to look after her son.
She worked for Charles and Diana at their country home in Gloucestershire until 1993.
As a royal employee, she had to sign a confidentiality agreement at the start of her eight years in their service.
Sunday Mail editor Allan Rennie has vowed to challenge the order.
He said: "This is a blow against freedom of speech.
"There are genuine and mounting concerns over the expenditure of the Royal Family and our report would have provided important new insights.
'No public interest'
"It is ridiculous that Americans have had the chance to read these revelations and we have not."
The Prince's lawyers said publication would infringe his privacy and serve no public interest.
In October 1995, a second court ruling entitled the prince to all profits from the book, but he was unable to claim them because Ms Berry was out of the country.
She has denied earning as much as £200,000 from the banned book.
The ruling comes after weeks of revelations from another former member of Prince Charles's staff, Paul Burrell.
One of his aides is accused of selling unwanted gifts from official visits and another is accused of rape.