Richard Ratcliffe said: “She’s been told she will appear in court on December 10.”
He said that he understood she would appear in court charged with spreading propaganda.
Mrs Zaghari-Ratcliffe, a project manager with the Thomson Reuters Foundation, was sentenced to five years after being convicted by an Iranian court of plotting to overthrow the clerical establishment.
She denies the charges.
Mrs Zaghari-Ratcliffe’s fate become a major political issue in Britain after Foreign Secretary Boris Johnson made remarks on November 1 that appeared to cast doubt on statements from her employer about what she had been doing in Iran.
The Thomson Reuters Foundation, a charity organisation that is independent of Thomson Reuters and operates independently of Reuters News, said she had been on holiday.
Mr Johnson told a parliamentary committee he understood she had been teaching people journalism before her arrest in April 2016.
He later apologised for his remarks.
The Thomson Reuters Foundation said she had not been training journalists in Iran.
Iranian state television has said Mr Johnson’s comments showed Mrs Zaghari-Ratcliffe’s guilt and claimed she was involved in spying.