A judge found there was sufficient evidence to try Maria de los Angeles Pineda with involvement in organised crime.
The wife of the ex-mayor of the Mexican town where 43 students disappeared in September is to be tried on suspicion of being involved in organised crime.But a federal court statement made no mention of any charges in connection with the students' disappearance.
The Mexican government says Maria de los Angeles Pineda and her husband, the former mayor of Iguala, handed the students over to a local drug gang.
Investigators say the gang then killed the students and burned their bodies.
Federal investigators blamed Jose Luis Abarca and Maria de los Angeles Pineda for ordering local police to hand the students over to members of a local drug gang, Guerreros Unidos.
A court statement said a judge had found evidence Maria de los Angeles had been acting as a financial intermediary for the gang and had helped protect it.