BBC News
The charges come a day after they appeared on Iranian state TV and said they had been “tricked” by an activist in Germany into speaking with the family of Sakineh Mohammadi Ashtiani.
The pair were arrested in Tabriz, north-west Iran in October.
They have only been identified as a reporter and a photographer.
Germany has said it is doing all it can to try to secure their release.
“The espionage charge for the two German citizens who came to Iran to stage propaganda and spying has been approved,” Malekajdar Sharifi, the head of the judiciary in Eastern Azerbaijan province, was quoted as saying by Reuters news agency.
Last month, Iran said the two had confessed to working as reporters in the country without the proper visas.
They travelled to Tabriz, where they interviewed the son of Sakineh Mohammadi Ashtiani – the 43-year-old Iranian woman whose sentence to be stoned for adultery has sparked international condemnation.
That sentence was suspended in July this year, but last month, reports emerged that Iranian courts were instead considering hanging her for the murder of her husband.
Ms Ashtiani’s lawyers insist she is innocent.