Fisher had finished shooting Star Wars Episode 8: The Last Jedi when she died in December 2016, aged 60, after suffering a heart attack.
Disney boss Bob Iger said Fisher appears “throughout” the new instalment and her image would not be recreated using special effects.
“We’re not changing ‘Eight’ to deal with her passing,” he told a conference at the University of Southern California.
“Her performance, which we’re really pleased with, remains as it was.”
Mr Iger said last year’s spin-off movie Rogue One: A Star Wars Story featured characters which were “digitally created” including one – Peter Cushing – whom had died.
“We’re not doing that with Carrie,” Mr Iger added.
:: Star Wars Episode 8: The Last Jedi is due to be released in December.